God is, and God is knowable. These two affirmations of faith form the foundation and inspiration of all religion. Christianity is distinctive in that it claims that God is known only in His self-revelation. In this self-revelation, however, the existence and nature of God are not subjects of definition. But man is called to follow the growing light in faith until he reaches the place where he can say: ‘I know whom I have believed.’ Yet that is not the end of the journey; in many respects it is only the beginning. And in the knowledge of God given in His revelation, there are few facts more perplexing to our understanding than that God is one and yet exists in three persons. This is the doctrine of the Trinity.
When we say that God is a Trinity we mean that He is a fellowship of three Persons, that He dwelt eternally in that fellowship of life and love and communion, the Father having fellowship with the Son, and the Father and Son having fellowship with the Spirit. It is thus that we conceive of a three-fold centre of self-conscious life within the Unity that we know as God. It is our faith that God is a Tri-unity .
Let us reflect that if God were not a fellowship of this kind, He would have been living in all the past eternity alone and aloof, when there was no created being and none with whom He could have fellowship. Such a God is to us inconceivable, a being alone in an empty universe. He could not be a God of love. Since love is self communication to another there cannot be love without an object to love. Such a God could scarcely be said to be alive.
This, however, is not the Christian conception of God, a unipersonal being who is alone and aloof. Rather God is a fellowship of three equal Persons in the blessedness of Deity, not needing anyone or anything from without to perfect that blessedness. There is thus complete and perfect fulfilment within the life of God, not needing a created universe to add to it. When we, therefore, say that there is but one God, constituting a fellowship of three equal Persons, that the Father, the Son and the Spirit are each God, and each a distinct self-conscious Person within the divine fellowship, we enunciate the doctrine of the Trinity.
We must accept, however, that despite all attempts at a philosophical interpretation, the doctrine of the Trinity is entirely a matter of revelation, and to our understanding largely a mystery, but, notwithstanding, a mystery that helps to explain many other mysteries. It is a biblical doctrine for which the Bible as a whole must be studied, and though we recognise the doctrine in the Old Testament, we do so only when we read the text under the illumination of the New Testament revelation. B. B. Warfield makes the analogy of a room richly furnished but dimly lighted. The introduction of light brings into it nothing that was not there before, but it brings into clearer view what was in it, and only dimly, or not at all, perceived before. True, the mystery of the Trinity is not revealed in the Old Testament, yet the doctrine underlies the Old Testament revelation throughout, though it is only here and there it comes clearly to light. We can affirm, indeed, that the Old Testament revelation is not so much corrected by the further revelation that followed it, but as perfected, extended and enlarged.
Generally speaking, the Old Testament view presses forward to its New Testament fulfilment. Thus it was that the writers of the New Testament saw the God they worshipped – Father, Son and Holy Spirit – in the God of the Old Testament. They sensed no incongruity between the monotheism of the Old Testament and the trinitarianism of the New. They, too, laid stress upon the unity of God, and they could not conceive of placing any other God – let alone any other two Gods – alongside Him. They, indeed, apply Old Testament passages to Father, Son and Spirit, almost without distinction.
The New Testament writings do not speak as if in this doctrine a new and fresh light broke upon their view. It was not the birth of a new conception of God that we have in the New Testament, and this explains why it is not at pains to proclaim the Trinity. Rather do the writers present as Father, Son and Holy Spirit, the God whom they and their fathers worshipped. Thus the New Testament, without any specific definition of the Trinity, is Trinitarian to the core. Christian faith becomes henceforward faith in the Three-in-one God.
The Old Testament
While there are some passages in the Old Testament where God as a plurality of Persons is suggested, there are others where the three Persons are seen operating. This is notably the case in so early a passage as Genesis I. In the record of the creation, there was God the Father, the Font of Deity, who created the universe; with Him was the Word through whom He operated; and also His Spirit, identical with Him in knowledge, who brooded over the primeval deep and gave both energy to matter and breath to living things.
This is true also of what we might call the Second Creation, the adumbration of the Kingdom of Grace. In Isaiah 61 we hear a divine Speaker declare: ‘The Spirit of the LORD is upon me, because the LORD has anointed me …’, a passage on which Christ in His synagogue sermon shed conclusive light (Luke 4: 16-21): the Lord, the anointing Spirit, and the One anointed. In the context of the redemptive history of Israel we find ‘angelophanies’ – the Angel of the Covenant, the Angel of the Presence – as a self-presentation of Jehovah who is one in essence with Jehovah and yet different from Him.
Thus we find, patent or latent, in the Old Testament the creative and redeeming God, the Word through whom He operated, and the Spirit of Jehovah, a Being of infinite intelligence who is closely connected with the revelation and application of the divine will.
The New Testament
When we pass over into the New Testament we have to reckon on its very threshold with the preaching of John the Baptist. It was clearly Trinitarian. Speaking of Jesus of Nazareth, John bare record saying: ‘I saw the Spirit descending upon Him like a dove and it abode upon Him’ (John 1:32), and again, ‘He that sent me to baptise with water, the same said unto me, ‘Upon whom thou shalt see the Spirit descending and remaining on Him, the same is He who baptiseth with the Holy Ghost.’ And I saw and bare record that this is the Son of God’ (John 1:33, 34). It is easy to see that John is there making reference to three distinct persons: the One who sent him; the Spirit that descended; and the One whom he recognised as the Son of God. This may go some way towards explaining how readily the first disciples, especially those who were first following John the Baptist, accepted the trinitarian teaching of their Master without question.
The coming into history of the Son of God was, of course, the occasion of bringing into clearer light the truth of the Triune God. On such occasions as the annunciation of the nativity, and the baptism in the Jordan, the three persons were represented. It need hardly be pointed out that the teaching of Jesus was trinitarian throughout. He spoke constantly of His Father, of Himself as uniquely the Son, and of the Holy Spirit who was to represent Him as He represented the Father. All three Persons are brought together in the Apostolic commission given by the risen Lord enjoining baptism ‘into the name of Father, Son, and Spirit’, all three uniting in common participation of the one Name. It is significant, indeed, that about 85 AD, when the Gospel of Matthew (a Gospel designed primarily for Jewish readers) was received by the Church, its concluding words should contain this remarkable testimony to the Trinity in Unity. Thus we can conclude that in the actual appearing of the Son in the flesh, and the actual outpouring of the Spirit consequent upon Christ’s exaltation, the facts were available which gave the doctrine its distinct place in the faith of the Church.
The rest of the New Testament, especially the Epistles, present the Triune God as a matter of experience, the Lord Jesus Christ introducing us into the love of God, and the Holy Spirit shedding that love abroad in our hearts, as enshrined in the form of the Benediction: ‘The grace of the Lord Jesus Christ, the love of God, and the communion of the Holy Spirit be with you all’ (2 Corinthians 13:14).
To Anselm is credited the yearning desire: ‘I long to understand in some degree the truth which my heart believes and loves. For I do not seek to understand that I may believe, but I believe in order to understand. For this also I believe, that unless I believe, I should not understand. ‘
What then is this doctrine of the Trinity that we must believe in order to understand it? Scripture does not offer us an elaborate or fully formulated trinitarian doctrine, but it contains the essential elements Out of which the doctrine has been constructed. The development of the doctrine owes much to three of the early Fathers – Irenaeus, Tertullian and Origen – with Athanasius and Augustine at a later date summing it up.
The two considerations requiring careful definition are the Unity of God and the Diversity in that Unity.
The Unity of God
The difficulty confronting the Church has ever been to preserve both the Unity and the Diversity within the Trinitarian Doctrine, the Unity within the Diversity. It is well known that Polytheism attributed a plurality of powers to deity, but separated them and worshipped each of them in isolation. Thus it was that there were altars put up to healing, fertility, prowess in battle, and so on. This emphasises the difficulty of conceiving of diversity in unity.
There is unity of nature or essence
The word used is substance: ‘Three Persons in one substance’ – substance here being non-material and incapable of partition or distribution. The divine nature is possessed alike and equally in all three Persons. Thus we do not have three individuals living independently of one another, even when they possess the same nature. With us, to take an example, we have a case of identical twins sharing the same nature, but they are two individuals. But with regard to God this is not a case of merely possessing the same nature, but the one nature, the one divine essence. Whatever we can predicate of God’s nature exists equally in each Person.
There is unity of character
The nature contains all attributes of the character in such a way that they belong to the very essence of God’s nature, and God would not be God without them. Since each Person shares in the fullness of God and therefore of His attributes, then each attribute is a true and full manifestation of God. Thus there can be no division, let alone conflict, between the revealed attributes [So much has been written about the ‘attributes’ of God, and so much confusion has ensued, that one is inclined to agree with John Calvin that the divine attributes should have been left unclassified. While it is true that since God’s character is moral it must be distinguished by certain attributes which belong to moral character wherever it exists, it has to be borne in mind that God’s nature is infinite, and that, therefore, His character does not permit of definition in terms of certain attributes. God is infinitely more than the sum of all His attributes. and His whole nature is present in each of the qualities that may justly be attributed to Him. Perhaps it would be better to understand the attributes of God as the special manifestation of God in each situation He is dealing with. In the presence of wrong He manifests Himself as just; in the presence of wickedness righteous. It must be remembered that God in the entire plenitude of His infinite nature is present in each manifestation He gives, so that we cannot say that His greater than His justice, or His righteousness is greater than His mercy. Where God is, He is all there. His mind, His heart, His will.] of God, nor can any attribute be weaker or stronger than another. There is a full expression of God in each.
There is unity of will.
The unity of God means that there is in God one will and everything in the universe is derived from the personal will of God. It animates the universe, throbs at the heart of every atom, and every form of life. Thus there can be no dualism in the universe, for there is but one mind, one purpose, and one self-expression This will of God is the final ground of existence and of everything that happens: He either brings it to pass, or permits it to come to pass.
The Diversity in the Unity of God
It is quite consistent with the unity of God’s will that there should be diversity in the expression of that will.
There is Diversity of Persons
The word ‘person’, first used by Tertullian, is not altogether self-explanatory. In the case of mankind a person is an individual in his own right, distinguishable from every other individual. Person in our case is the individual substance of a rational nature, possessing self-existence as well as self-consciousness. But ‘person’ applied to the Trinity does not mean individual self-existence. The three Persons rather suggest a three-fold existence, a three-fold self-distinction within the divine Being, and these distinctions are personal, so that there is an ‘I-Thou-He’ relationship, constituting fellowship, a genuine communion, and authentic love. In our worship we are taught to address God in His personal distinctions as Father, Son and Spirit.
There is a Diversity of Properties
This means that the Persons are not only distinct, but that they differ from one another in regard to their particular properties and their eternal relations, the Father begetting the Son, the Son begotten, the Spirit proceeding from Father and Son.
It Means that there is Diversity of Operations.
It is said that the Father originates: He is the source of all there is.
The Son, coming forth from the Father, is the Word who communicates the divine thought. He is eternal rationality, ‘the Light that lighteth every man that cometh into the world’ (John 1:9).
The Spirit is the quickener and life-bringer, the executor of the divine will who puts it into operation. He is the Holy Spirit who conveys the radiance of God’s holiness to the moral universe.
The Implication of the Doctrine
The implications of God’s Being as Tri-personal have far-reaching meaning for the moral universe as a whole, and become one of the richest discoveries of the human soul.
It means that God is revealable
Before creation took place there was self-revelation within the Trinity, the Father revealing Himself to the Son, and the Father and the Son to the Spirit. Thus self-revelation was an exercise of God from all eternity. It is as natural to God, as it is for the sun to shine, and in shining to reveal and communicate. When God willed to create a moral universe it meant letting His revelation out to His creation.
It means that God is communicable
Since God is Himself a circle of fellowship, He can let that fellowship go out to His creatures. He can communicate Himself to them in their capacity to receive. This is what happened when He created man in the likeness of His image. He called man into His fellowship and gave him the capacity to receive and respond. This is what happened supremely when God came to redeem men: He let fellowship bend down to reach fallen man and lift him up.
It means that God is the basis of all true fellowship in the world.
Since God is within Himself a fellowship, then His moral creatures are built on the same fellowship pattern, and they find fullness of life only within fellowship. This is seen in marriage, in home, in society, but above all in the Church whose koinonia is built upon the fellowship of the Three Persons. Christian fellowship is therefore the divinest thing on earth, the most like the life of God. It is the earthly counterpart of the divine life, for which Christ prayed on behalf of His followers:
‘That they may be one as Thou Father art in Me and I in Thee, that they may be one also in Us’ (John 17:21).
In short, it gives variety to the life of the universe.
There is diversity in the life of God, and if the creation be a manifestation of God we would expect a diversity of life there too. And there is. All the wonders of creation, all the forms of life, all movements in the universe that draw out the diligent search and research of the scientist, all are a reflection, a mirroring, of the manifold life of God.
Above all, it gives richness to our experience of redemption.
When we come to understand that God, the triune God, was engaged in man’s redemption – the Father designing it, the Son executing it, and the Spirit applying it – the experience of salvation is enriched a thousand fold in the love of the Father, the grace of the Son, and the communion of the Spirit. And so we come to know ourselves as the children of the Father, as redeemed by the Son, and as indwelt by the Spirit. Thus we know and enjoy by faith the Triune God in our personal experience of redemption. This has led the great Scottish divine of a few generations past, Dr. John (Rabbi) Duncan, to say: ‘I am inclined to think that the great end of human redemption is the full manifestation … of-the divine Tri-unity.’