Thoughts on the Trinity

One of the fascinating things about theology is that questions of form and questions of substance are often intertwined.  This is certainly true of the doctrine of the trinity.  The moment we address it we face the question of order: Do we treat it before or after the doctrine of the attributes?


This is one of the fundamental issues raised by Karl Rahner, who on the very threshold of his discussion of the trinity speaks of, “The  Problem of the Relation between the Treatises ‘On the One God’ and ‘On the Triune God’”.[i] Rahner is profoundly critical of “the separation immemorially taken for granted between the two treatises” and traces it back to Thomas Aquinas, who, he alleges, departed from the order not only of his Scholastic predecessors such as Peter Lombard, but also from the order of the Apostles Creed, which treats the attributes within its overall trinitarian structure, considering the essence as the essence of the Father, “the almighty maker of heaven and earth”.  Although his meaning is by no means clear, Rahner’s argument appears to be that the first topic in theology should not be the doctrine of God in general, but the doctrine of God the Father, considered as “the unoriginate origin of divinity and reality”.[ii]

The problem with Aquinas, however, was not merely that he separated the doctrine of God from the doctrine of the trinity, but that he treated them as if they belonged to different epistemic universes.  The doctrine of God covered “truths of reason”: truths such as the existence, unity and simplicity of God, which can be known by natural reason and proved by “a cogent demonstration, as when natural science argues about the velocity of heavenly bodies”.[iii] Aquinas draws a sharp distinction between such truths and truths of faith, and regards them not as parts of the Creed, but as preambles to it.[iv]

The doctrine of the trinity, by contrast, is for Aquinas a truth of faith, undiscoverable by reason.   Whereas in the case of the existence of God we first prove it and then accept it, in the case of the trinity we first accept it and then prove it.[v] It is a truth delivered not by philosophy but by Christianity, and discoverable not by reason but by revelation.

This dualism is far more serious than the mere order in which Aquinas treats the doctrine of God and the doctrine of the trinity.  It presupposes two different roads to God.  For the first part of the route we have to take the road of reason; when this peters out we have to take the road of faith.  Over against this, we have to insist that there can be no autonomous human road to the knowledge of God.  God alone knows God, and humans can know him only to the extent that he shares with us a little of what he knows about himself.  We are dependent for all our knowledge on God’s self-revelation, and we can make absolutely no progress until we accept that revelation in faith.  Faith is the prelude to all understanding, not merely in the chronological sense but in the sense that without faith there can be no understanding.  Belief in the existence of God is not a conclusion from reasoning, but the precondition of reasoning.  In this sense the principle which Aquinas laid down with regard to the trinity applies to the whole doctrine of God: first we accept, then we prove.  The truths of Genesis One, no less than the truths of John One, are truths of faith: by faith we believe that the world was made by the word of God (Hebrews 11:3).

What, then, of the relation between the two treatises, De Deo and De Trinitate?  It is tempting to invoke the principle, methodus est arbitrarius and simply walk away from more elaborate discussion.  Whether the topic be predestination, regeneration, the trinity or whatever, there is no normative locus for treating them.  The Canon does not lay down that a topic must occupy a certain position in a creed or a summa.  It is simply a matter of good order; and good order itself may vary according to circumstances.

But there is one clear argument in favour of the order followed by Aquinas and so many of his successors: it is the order of revelation.  The Old Testament is virtually silent on the doctrine of the trinity and even on such foundations of that doctrine as the fatherhood of God.  It is entirely concerned with the doctrine De Deo, seeking to establish the doctrine of the divine unity in a world where polytheism was all-pervasive.  With undeviating consistency it focuses on one great truth:  “Hear, O Israel, Jahweh our God is one” (Deut. 6:4).  The Old Testament offers but the barest hints of a plurality in the divine: so bare, indeed, that, as B. B. Warfield points out, “none who have depended on the revelation embodied in the Old Testament alone have ever attained to the doctrine of the Trinity.”[vi] This is not to deny that there are clear indications in the Old Testament of both a divine Messiah and a personal Spirit, but these strands are nowhere brought together either in a doctrine of the incarnation or in a doctrine of the trinity.  The faith of an Abraham, a Moses, a David and an Isaiah is in God undifferentiated: the one God in whom there is such fullness of godhead that he is sufficient in himself to be the one Lord of the whole earth.  We should never forget that this emphasis on both the unity of God and the exclusive lordship of Jahweh is the single most important element in the Trinitarian creed.  There is but one world, and it has but one God.  As Barth points out, faith in the triune God is not a faith with three objects.[vii]

It is equally important, however, to emphasise that the Old Testament does not set forth a bare monotheism or espouse an apophatic theology which affirms nothing except that God exists and that he is one.  On the contrary, it sets forth the perfections and attributes of this God so completely and so memorably that the New Testament has little to add.  The God of the Old Testament is no limp, colourless being.  He is eternal, almighty, all-knowing and all-present.  He is holy and jealous, yet loving, forgiving, merciful, and compassionate.  Above all, he is unshakeably loyal: the God of hesed.  He never walks out on his people; and he never allows them to walk out on him.

It is only in the light of this doctrine of God that we can understand the doctrine of the incarnation.  When the New Testament calls Christ theos it means this theos:  the God of Genesis One; the God of Abraham, Isaac and Jacob; the God of Horeb and the Burning Bush;  the God of the soaring prophecies of Isaiah.  When it calls him kurios it means that he is Jahweh, that he possesses all the attributes of the God of Israel and that his earthly story is but the continuation of that divine story which began in the Beginning and ran through the call of Abraham, the Exodus and the miracle of Mount Carmel to the mission of the last of the Prophets, John the Baptist.  And the most remarkable thing about the Continuation is that the New Testament does not seem to think it remarkable at all and shows not a trace of consternation or embarrassment over being called to bear witness to this seismic modification of the Old Testament doctrine of God.

All this already makes clear that wherever we place our doctrine of the trinity in relation to our doctrine of God we cannot keep the two separate.  The doctrine of the trinity is a direct outcome of the doctrine of the incarnation, and that doctrine is unintelligible without some prior doctrine of God.  Conversely, when discussing the doctrine of God we cannot forget either the doctrine of the incarnation or the doctrine of the trinity.  Here there is a close analogy to the perspectives of the gospels.  These are written in narrative form and tell the story from his birth to his death.  The resurrection comes only at the end of the narrative, yet the whole narrative is told from its standpoint; and because it is told from the standpoint of the resurrection it is told from the standpoint of the divine sonship of Jesus.  The same has to be true for theology, especially if, as Barth once declared, all theology has to begin with the resurrection.  The doctrine De Deo can be no exception to that.  The Christian theologian cannot for a moment forget that the God he seeks to proclaim is the God and Father of our Lord Jesus Christ.  Nor can he forget that it is in his Son that God has given himself a face, and that we can therefore neither deny nor suppress any aspect of that face.  The world must see the whole face, because even what was revealed before his advent is now brilliantly illuminated by the Glory which came to dwell among us.  Indeed, it is not even enough to argue that theology must start with the resurrection.  We have to invoke what Jurgen Moltmann called “Luther’s lapidary statement: Crux probat omnia.”[viii] The cross is indeed the test of everything, including (especially) our doctrine of God.  How can we discuss the divine love or the divine compassion or divine passibility or divine holiness or divine power as if the cross had never happened; or as if we could not let it shine its light on the doctrine of God because, according to our “system”, at the point where we are treating the doctrine of God we do not “officially” know about the doctrine of the incarnation?  We cannot; and once we admit this we must take the further step of setting forth our doctrine of God not only in the light of the resurrection and of the cross, but no less in the light of Pentecost.  Not that the Spirit is the face of God in the same sense as the Son!  But there can be no Christian doctrine of the divine presence and the divine power except as these are linked indissolubly to the mission and ministry of the Holy Spirit.

This insistence that though the doctrine of the trinity may be treated before the doctrine of God it cannot be treated in isolation from it harmonises well with an observation made by Robert Jenson on the Church Dogmatics of Karl Barth.  On the face of things Barth still adheres to the old method of dealing successively with each of the loci of theology (though he discusses the doctrine of the trinity before the doctrine of God.  In reality, his treatment of each topic is virtually a system in itself.  It is as if with each volume Barth were beginning afresh, developing “a whole theology organised around a major theme.” (29)  Whatever we may think of Barth’s conclusions, there can be no doubting the validity of such a method.  The doctrine of the trinity attracts to itself the light of the whole truth; and conversely it itself illuminates every other nook and cranny of truth.  Revelation, predestination, creation, providence and redemption are all Trinitarian.

How does this relate to Rahner’s suggestion (if I understand him correctly) that the attributes be discussed under the first article of the Creed, “I believe in God the Father, almighty maker of heaven and earth”?  On the face of things, this also allows us to proceed by way of Barth’s method, the discussion of the Father opening up the way into a discussion of the Son and the Holy Spirit.  Indeed, such a discussion is inevitable, since He is not the Father apart from the Son.  Yet Rahner’s approach carries the clear risk of compromising the equality of the three persons of the trinity, so clearly set forth by, for example, the Athanasian Creed (25, 26)): “in this trinity none is before and none is after; none is greater and none is lesser, but the whole three persons are coeternal and coequal.”  This equality is already jeopardised in the Apostles Creed by the ascription of creation exclusively to God the Father, as if he alone were “the almighty maker of heaven and earth”.  A fuller doctrine of creation would have to take account of the roles ascribed to the Spirit in Genesis 1:2, to the Logos in John 1:1-5 and to the Son in Colossians 1:15-18 and Hebrews 1:2.  To link the divine essence primarily to God the Father (we speak with trembling) would seriously increase the risk of misunderstanding, creating the impression that the essence belongs to the First Person in a supreme sense and to the Son and the Spirit only in an inferior sense.

Rahner does, of course, have a ready explanation for his procedure: the Father is “the unoriginate origin of divinity and reality”.[ix] But what if this is the very idea we need to avoid, however familiar the idea of the Father as fons et origo may be to us from Patristic theology?  Is it not an idea which we must challenge root-and-branch?  The Father is not the origin of the divine essence because divinity can have no font or origin.  To think otherwise is to posit a reality more ultimate than God: the fons et origo of divinity.  Nor can we speak of the Father as the origin of the Son or of the Spirit.  The essence of the Son and the Spirit are not merely equal to that of the Father.  They are numerically identical with it: otherwise we have three divine beings.  The divine essence in the Son is unoriginate.  True, he is begotten, but to beget is not to originate:  a point conserved in the ancient formula that the Son was agenetos (unoriginate) though not agennetos (unbegotten).  This point would later receive clarification in Calvin’s resistance to those who argued that the Son was not autotheos (God in his own right), but was “essentiated” by the Father.  Calvin gave the robust reply that either the Son was God ex se ipso (God from his very self) or he was not God at all.[x] These are points to which we may return.

Any authentically trinitarian discussion of the divine attributes must introduce not only God the Father but equally and simultaneously the Son and the Spirit.  On this, Barth was absolutely right:  “In a dogmatics of the Christian Church we cannot speak correctly of the nature and attributes of God without presupposing that it is God the Father, Son, and Holy Spirit of whom we are speaking.”[xi]

The ontological and the economical trinity

Another issue which Rahner has placed firmly on the agenda for modern trinitariann discussion is what he calls, “The Axiomatic Unity of the ‘Economic’ and ‘Immanent’ Trinity”:[xii] a position warmly endorsed by other participants in the discussion, such as Jurgen Moltmann.[xiii] This stresses that the God who comes to us in revelation is God as he is in himself.   It is obviously fundamental to our whole procedure.  Without this unity between the revealed and the immanent we can know nothing about the inner reality (the ontology) of God.  But the principle requires some clarification.

We need to reflect, first of all, on the relation between revelation and redemption.  The only reason that we know anything at all of the interior relations of the godhead is that the Father’s Son has entered history and brought with him his (and the Father’s) Spirit.  The purpose of that entry, however, was not merely, or even primarily, revelation.  Its primary purpose was redemption (Mark 10:45).  The revelation itself, as Warfield points out, “was made not in word but in deed.  It was made in the incarnation of the Son, and the outpouring of God the Holy Spirit.”[xiv] This warrants the conclusion (which Warfield himself draws) that, the revelation of the trinity was incidental to the accomplishment of redemption.  Yet the use of the word “incidental” must not tempt us to think that revelation was not important.  On the contrary, revelation is itself a redemptive act: indeed, a major and indispensable element in the series of redemptive acts.  There can be no salvation without knowledge, and no knowledge without revelation.  It is for this very reason that the Father has delivered to the Son all those things which he has hidden from the wise and prudent (Matthew 11:27).  The Redeemer must be Prophet, as well as Priest and King.

Yet in the case of the trinity (though not only in the case of the trinity) that revelation is given primarily in certain great events.  This is why, prior to these events, there was scarcely an inkling of this doctrine; and why, on the other hand, the incarnation has such tremendous epistemic as well as redemptive impact.  When the moment arrives to accomplish our salvation the Lord our Redeemer comes to us as a threefold Redeemer.  He comes as the Father, the Son and the Holy Spirit.  This is established at the very outset of Christ’s mission when, at his baptism, the three persons appear together in the same frame: the Son who is baptised, the Spirit who descends on him and the Father whose voice is heard from heaven.  This passage is sufficient of itself to banish Sabellianism.  But the same threefold-ness in the redemptive lordship also appears in the critical moments of redemption, not least in the cross, where the Father delivers up his own Son and where the Son offers himself through the Holy Spirit.  It appears, too, in the resurrection: this is why Paul can speak of  “the Spirit of him who raised Jesus from the dead” (Romans 8:11); and no less so at Pentecost, where Christ, having received the promise from the Father, poured out the Holy Spirit (Acts 2:33).

The same three-fold agency appears in the Christian experience of salvation.  Tempting though it is to see soteriology as the specific domain of the Holy Spirit it is clear that here, too, the whole divine Name is involved.  This is not to deny the Spirit’s role.  He is fully involved, but involved only in association with the Father and the Son.  This is why the Book of Acts is the book of the acts of the risen Jesus, who is still giving eternal life to those the Father has given him (John 17:2).  And this is why those specific moments in the ordo salutis which the older Reformed theology used to ascribe to the Holy Spirit now have to be seen as equally due to God the Father, who not only predestinates but effectually calls and glorifies his own children (Romans 8:30), as well as keeping and sanctifying them (John 17:15-18).  The three-fold Saviour is clear in every phase and every aspect of redemption.

Yet however dramatic the great events of redemption they do not yield their meaning by themselves.  The event needs the word, and just as the Pentateuch interpreted the Exodus so do the gospels and the epistles interpret the Christ-event.  It is true, of course, as Rahner recognises, that “the Scriptures do not explicitly present a doctrine of the ‘immanent’ Trinity”.[xv] This is why in formulating the doctrine of the trinity we may seem to have to rely heavily on scripture testimony to the ‘economic’ trinity.  Nevertheless, if we had no biblical pointers to a pre-economic and pre-temporal state of the godhead we would hardly dare to infer the immanent trinity from the economic, no matter how clear the evidence for the latter.  The Johannine prologue may not furnish us with a full-blown doctrine of the trinity, but it certainly draws aside on relations between the persons of the godhead anterior to the incarnation.  In the Beginning, the Word was already in being; and in the Beginning, before there was Light, there was with-ness.  The Word was with God (John 1:1).  The Christ-hymn of Philippians 2: 5-11 likewise points us to the state of the pre-incarnate Christ: a state in which he already existed in the form of God, not as alone-God, but as the Son of his Father who, on the completion of his obedience would hyper-exalt him.  In the same way, Hebrews 1:1-4 opens the window on a situation in which, prior to his advent, the Son played a central role in creation, and did so because, quite independently of the incarnation, he was the effulgence of the Father’s glory and the express image of his being.

The immanent or ontological trinity is not, therefore, simply an inference from the economic trinity as disclosed in the process of redemption.  That is an inference we would not by ourselves have dared to make.  We make it only because the scriptures encourage us to do so.  On the other hand, we cannot lightly affirm that what the “economy” itself reveals is a trinity.  To be confident of that we need to be sure, first of all, that the coming of Christ is indeed an incarnation.  That depends entirely on whether the Man Christ Jesus is God.  This, of course, is the testimony of the early church, but we need a deeper foundation than that.  Such a foundation we find in the self-consciousness of Jesus.  As he dwelt among us in all his physical, mental, emotional and social ordinariness, who did he think he was?  The answer is absolutely clear.  He thought he was God.  He thought that he and the Father were One and that he no less than the Father could send the Spirit. He thought that his powers were such that supposing all the souls in the world came to him with all their burdens he could carry them all (Matthew 11:28)  He thought that before, above and beyond the “economy” he was the eternal, pre-existent Son of God.  It is this alone which makes it possible for us to speak of an economic trinity.

But what does this signify?  It signifies that the one who comes to us in redemption, Jesus Christ, is God himself, and God as he is in himself: not an archangel or a superman or a Spirit-filled man or any mere messenger or plenipotentiary, but the one and only God in the fullness of his being, personhood, attributes, functions, attitudes and prerogatives. In him, the kingdom comes because the King comes.   The incarnate Logos is the immanent Logos, who speaks forth the heart of God.  He is one in being (homoousios) and one in love (homoagape) with God the Father.  In him, God himself is bearing the cost of our salvation.  In his face we see the glory of God, in his washing of disciples’ feet we see God doing something “matchless, God-like and divine” and in his cross we see God himself bearing the whole cost of our redemption.  In him, the all-knowing, all-powerful and all-present divine love is making our salvation his main business.

That needs no qualification.  Yet the relation between the ontological and the economic trinity does need to be defined with some care.  For example, we cannot simplistically assume that relations between the Father and the incarnate Son are identical with relations between the Father and the pre-incarnate Son.  Nor may we unreflectingly identify the relationship between God and the Mediator with the relationship between God and the eternal Son.  There may be things true of the one set of relationships which are not true of the other.  The reason for this is simple.  The incarnate Christ is not merely the Son: he is the Son as Mediator.  This office is clearly based on his sonship, but it is not inherent in it.  He holds it voluntarily, prompted by his love for the church, and it involves him in a whole new set of relationships.  He must take the form of a servant (Philippians 2:7), place himself under the law (Galatians 4:4) and undertake to finish the work given him to do (John 17:4).  He must practise kenosis, set out on a long journey of humiliation, live within the limitations of creaturehood, and experience a dependence and accountability utterly foreign to his pre-existent state.  He must enter into an entirely new relationship with his Father: one in which he must be upheld and encouraged by the Father; one in which he has to speak not his own words but the Father’s; one in which he knows only what the Father reveals to him; and, above all, one in which he has to acknowledge, “The Father is greater than I.” (John 14:28).

We cannot uncritically read all this back into the immanent trinity.  Otherwise we evacuate the kenosis of its meaning and posit an incarnation without humiliation.  At every point we have to be aware that any single aspect of Christ’s relationship with his Father may reflect not the eternal, ontological reality, but the implications of kenosis.  At the same time we have to bear in mind that the incarnation is permanent.  In the Son, the two natures, human and divine, are united for ever; and this carries with the fact that Christ is for ever the Last Adam, with all the responsibilities that that involves.  These do not cease when he brings the church home to glory.  That is but the end of the beginning.  There can be no temporary messiahship.  Christ is destined to be for ever the First-born among God’s children (Romans 8:29) and as such the successor to all the privileges, mandates and responsibilities that God gave to the First Adam.  He will have dominion over the world to come, but that will be an Adamic dominion (Hebrews 2:8-9); and at the same time he will carry the burden of shepherding his people (Revelation 7:17).  He will do so, of course, in his glorified humanity, but even glorified humanity is still humanity, creaturely and dependent.  He himself will feed from those very fountains from which he feeds his people (Revelation 7:17).

He will forever, then, sustain two different sets of relations to his Father: one as the eternal Son, the other as the Last Adam.  They are totally congruous, the image of God being common to each (though in different ways): but they are nevertheless distinct.

But there are also things true of the incarnate Christ in his own person which we may not read back into the divine ontology.  It is inevitable, of course, as Barth points out, that since Christ is the revelation of God the focus of both the Bible and of subsequent Christian reflection falls disproportionately on him, rather than showing an equal interest in all three persons.[xvi] But there are things true of the earthly Jesus which are not true of the eternal God: things which amount to a divine word about humanity rather than a divine word about divinity.  The fact, for example, that Christ died does not mean that God is mortal.  Nor does the fact of Jesus not knowing (Mark 13:32) prove that God is ignorant; or the fact of his being occasionally impotent (Mark 6:5) indicate that God may sometimes be powerless; or the fact that Jesus was “amazed” warrant our concluding that God can be taken by surprise.  Yes, the eternal, self-contained triune God is the one who comes as our Saviour in Jesus Christ, but this gives us no carte-blanche to read back into the nature of God every trait and limitation that characterised the Jesus of the gospels.

This involves, among other things, that we cannot build a doctrine of divine passibility simply on the fact that Jesus suffered.  That may indeed prove that pain, unlike sin, is not incompatible with divinity, but it still remains open to us to argue that he felt the pain only in his human nature and that this tells us nothing of his divine.  A doctrine of divine passibility may find support in the fact that the Son of God came towards our pain, but it also needs the support of wider biblical and theological considerations.  Among these are considerations drawn from the doctrine of the trinity itself.  One of these is highlighted by Jurgen Moltmann.  Moltmann picks up on the age-old principle that the external or out-going acts of God (the opera ad extra) are acts of the whole trinity, or at least acts in which all three persons are involved.  But he suggests that corresponding to this there is another principle: the principle of the passiones trinitates ad intra.[xvii] If this principle holds, then, just as the acts which go out from God are acts of all three persons, so the sufferings which come into God are experienced by the entire trinity.  In the One the Three suffer.

The truth or otherwise of this can be assessed only in the light of such key Trinitarian concepts as the homoousion (the three persons are consubstantial)and the circuminsessio (the mutual indwelling of the three persons).  But that will have to wait.

[i] K. Rahner, The Trinity (Tunbridge Wells: Burns and Oates, 1970) 15

[ii] The Trinity, 15,16

[iii] Summa Theologiae, 1a.32,1

[iv] Summa Theologiae, 1a.2,2

[v] Summa Theologiae, 1a.32,1

[vi] B. B. Warfield, Biblical and Theological Studies (Philadelphia: Presbyterian and Reformed, 1952) 29

[vii] K. Barth, Church Dogmatics I.1 (Edinburgh: T&T Clark, 1936) 401

[viii] J. Moltmann, The Crucified God (London: SCM Press, 1974) 7

[ix] The Trinity, 16

[x] J. Calvin, Institutes I.XIII, 23

[xi] Church Dogmatics I.1, 358

[xii] The Trinity 21

[xiii] J. Moltmann, The Trinity and the Kingdom of God (London: SCM, 1981) 158ff

[xiv] Biblical and Theological Studies 33

[xv] The Trinity, 22

[xvi] Church Dogmatics I.1, 361

[xvii] The Trinity and the Kingdom of God 160