What makes the Holy Trinity one?

C.C. — Yes; that is another line. It is a different word. Now, if there are persons in the Godhead, and yet the Godhead is a unity, in what sense or senses are the three persons one? They are one in substance; one in nature; one in life; one in purpose, plan and counsel.

How, then, it may be asked, do we sustain our doctrine of eternal generation and at the same time obviate such a conclusion? We sustain it thus. We have already shown that there is a distinction between the Essence of God, which is one and self-existent, and the Personality of the Three Persons in the Godhead. Which is threefold, and thus intercommunicative, and so far dependent. We have to lament the inadequacy of language, or at least of our own language, to set such sublime mysteries forth; but the doctrine of a Trinity in Unity can only be so defended. The Unity of God implies self-existence; the Trinity in Unity implies relationship. Thus as regards the Unity of Essence Christ is self-existent; but as regards the Trinity He is begotten. He is therefore not a begotten God, though He is a begotten-Son. This explanation may be called mystical and obscure; but on such deep and incomprehensible subjects all thought fails and all language falters. Yet as we are sometimes called upon to state or defend our views of divine truth, it is desirable to have clear views of what we believe, and to express them as plainly as possible. We believe, then, that there are Three Persons in the Godhead, and that these are distinguished from each other by certain personal relationships, and that these personal relationships are not covenant titles, names, or offices, but are distinctive and eternal modes of existence. We are thus preserved from Sabellianism on the one hand, which holds that there is but one God with three different names; and Tritheism on the other, which makes three distinct Gods. But believing in a Trinity of Persons, in the Unity of the divine Essence, we say that the father is a Father as begetting; the Son is a Son as begotten; the Holy Spirit is a Spirit as proceeding. If, as imputed to us, we were to say that the Son is “a begotten God,” we should deny Him self-existence in His Essence, as One with the Father and the Holy Spirit; as if we should say that He is a Son by office or by His incarnation, we should deny, as Mr. Crowther does, His true, proper and actual Sonship. To sum up the whole in a few words, it is in His Person, not in His Essence, that He is the only-begotten Son of God. Dr. Gill has opened up this distinction with his usual clearness and ability in the following extract from his “Body of Divinity”:

When I say it is by necessity of nature, I do not mean that the divine nature, in which the divine Persons subsist, distinguishes Them; for that nature is one and common to Them all. The nature of the Son is the same with that of the Father; and the nature of the Spirit the same with that of the Father and the Son; and this nature, which They in common partake of, is undivided; it is not parted between Them, so that one has one part, and another a second, and another a third; nor that one has a greater and another a lesser part, which might distinguish Them, but the whole fullness of the Godhead is in each.

So we must be careful in using the terms, first, second and third Persons in the Trinity, not to think there is any difference in importance. The Father is God; the Son is God; the Spirit is God—the Spirit equal in nature and substance to the Father and the Son. If the three Persons of the Godhead are each of them God, it does not follow that there are three Gods. That were impossible. There can be only one God, supreme and unique. Orthodox Christendom believes in three Persons in the Godhead, yet one God, indivisible and unique—the three Persons in the Godhead with one will, one purpose, each sharing to the full every thought and desire and purpose in the minds of the others. We may not, nay cannot, comprehend this. It is a mystery hidden in the Godhead, yet the Godhead is pleased to reveal Itself as Father, Son, and Holy Spirit.

The Holy Spirit is God, as the Father is God, and the Son is God, in the Unity of the Godhead, of One Substance, One in knowledge, counsel, will, purpose. We are obliged in speaking of them together to put their names in a certain order. Scripture gives the order in baptism, that those baptised are baptised in the name (not names) of the Father, and of the Son, and of the Holy Ghost. (Matt. 28:19). But we must be careful not to make any distinction in the Persons of the Godhead in the way of One being more prominent than the Other.

Gathering up our thoughts from these and other Scriptures such is the unity of the Godhead that there cannot be one thought in the Father’s mind that is not altogether shared and approved by the Son and the Spirit—not one intention or purpose in the mind of One of the Persons in the Godhead but what is fully shared and endorsed by the other Two Persons in the Godhead, for God is One.

Without the Trinity love was not known, righteousness, holiness - the spiritual nature of God and purity as such. That is, He never was revealed as He is and always was. All the true nature of God, that is, what He is, without the Trinity is unknown. The Father wills; the Son quickens whom He will; but because we have separate wills, why necessarily have the Father and the Son? The Spirit distributes to whom He will; but this is not separate from the will of the Father and the Son. They have not the same counsel but one counsel, mind, purpose, thought; yet they act distinctly in the manifestation of that counsel. The Father sends the Son, and the Son the Spirit. Yet when the Son comes, He is not thereby separate from the Father. "The Father that dwelleth in me, he doeth the works." So He casts out demons by the Spirit of God; yet He casts them out. There is unity in all that constitutes oneness when we speak spiritually - not unity as one by arriving at the same things, or union, or by being united, as we are by having only one Spirit dwelling in all, but - by being one in eternal being; so that all else flows from that one will and counsel, yet so as that distinction in action in that will is revealed to us: not distinct will, but distinct willing.

Thus we see that there could be no full revelation of God, but through the Son by the Spirit, and thereby of the Father. The full revelation of the one God is only thus - Father, Son, and Holy Ghost. This, this only, is what the one God is, one identity of will and being, so that they are essentially one and one only, yet distinct in willing and acting (and we can distinguish them in willing and acting: hence we commonly speak of persons), yet never willing or acting but in the common will and unity of nature.

The disciples could not fail to realise that He was the Son of the Father. Our Lord spoke much of the Father. “I and My Father are One” (John 10:30), He affirmed, He was ever in communion with the Father. The Father was not the Son. The Son was not the Father. Yet, with the Spirit, they are ONE God, one in purpose, counsel, will, knowledge, movement. It is no wonder that one of the disciples, writing for the rest, could say, “And the Word was made flesh, and dwelt amongst us, (and we beheld His glory, the glory as of the only begotten of the Father), full of grace and truth” (John 1:14).

Could love assure its objects of more? His love would impart to them the certainty of His own deepest joy, His Father's love as sure as His own; and so He closes His communication with it. "My Father Who hath given to Me is greater than all, and no one is able to seize out of the hand of My Father. I and the Father are one." Here we rise into that height of holy love and infinite power of which none could speak but the Son; and He speaks of the secrets of Godhead with the intimate familiarity proper to the Only-begotten Who is in the Father's bosom. He needed none to testify of man, for He knew what was in man, being Himself God; and He knew what was in God for the self-same reason. Heaven or earth made no difference, time or eternity. Not a creature is unapparent before Him, but all things are naked and laid bare in His eyes with Whom we have to do. And He declares that the Father Who had made the gift resists all that can threaten harm, and as He has given to Christ, so He is greater than all, and none can seize out of His hand. Indeed, the Son and the Father are one, not one Person (which ἐσμεν with every other Scripture bearing on it, refutes), but one thing, ἓν, one Divine nature or essence (as other Scriptures equally prove). The lowliest of men, the Shepherd of the sheep, He is the Son of the Father, true God and eternal life. And He and the Father are not more truly one in Divine essence than in the fellowship of Divine love for the sheep.

We are, for example, taught in Matt. 28:19 that Father, Son, and Holy Spirit are comprehended under a single “name.” Though there are three Persons, there are not three names, but one; there are not three "grades," but one Tri-personal Unity.* The Lord also said, "I and the Father are One" (John 10:30); and "The Son can do nothing of Himself save whatever He sees the Father doing"; and "The Father knows Me, and I know the Father" (John 5:19; 10:15). These and other passages teach unity and community of nature between the Father and the Son.