What does it mean that the Trinity is God in three Persons?

Here in this very majestic declaration of the Oneness of the Godhead, care is taken to state it consistently with the truth afterwards revealed concerning the Three Persons of the Godhead—Father, Son and Spirit. These Three Persons, of one Substance, completely united in thought, will, purpose, counsel, are not three Gods, but One God, not a tritheism, but a Holy Trinity. We cannot understand the mystery of all this, but this truth lies at the very foundation of the Christian faith.

The Father is God, the Son is God, and the Holy Spirit is God; yet there are not three Gods, but one God, "God is one" (Gal. 3:20; 1 Tim. 2:5). Baptism is to the name of the Father and of the Son and of the Holy Spirit," we are told in Matthew 28:19. This indicates for us the trinity of Persons in the Godhead, all of whom share in that supreme glory.

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 word "Trinity" is not found in scripture; the expression "justified by faith only" is not found in scripture; yet I need not justify them to you as human expressions of essentially fundamental truths. I have no better words, and I use what I find commonly used to express what I believe in my inmost soul... So with the word "Person" applied to the Godhead. It is not scriptural; but I have no better word for One who sends, is sent, comes, goes away, wills, distributes, and does distinctive acts.

In human language when we speak of a person, we think of separate entity, separate existence, separate will, different characteristics, thoughts and plans peculiar to each person, not shared with any others. Carry that human thought into the subject before us, and the truth of the Trinity is entirely perverted and lost.

Here in the very assertion that there is one God, care is taken to show that the UNITY of the Godhead embraces Three Persons—One in substance, power, will, wisdom, knowledge and counsel. No mind of man, however acute, can fathom this mystery. We know the truth of it from revelation alone.

God has revealed Himself in a variety of ways through the ages, but only in these last days, when He has spoken to us "in Son," has He been revealed in Trinity. The Old Testament gives indications of three Persons in the Godhead, by using the word for God, Elohim, which is in the plural. Indications, yes; but no revelation. In the New Testament the Trinity stands fully revealed, as Father, Son and Holy Spirit, and ONLY thus.

It was not indeed until the baptism of our blessed Lord that the whole truth of the Trinity came out. Then God spoke from heaven; His beloved Son was on the earth; and the Holy Spirit descended and remained upon the Son.

We have had the will of God as the source of our salvation, and the Saviour's work as the efficacious means. There now follows the no less indispensable witness of the Holy Spirit as the unfailing power of bringing our souls into the possession and knowledge of the blessing. Thus each person of the Godhead has His appropriate place, and all contribute to this end as worthy of God as it is needed by man.

First the Son through Whom all has been wrought on the cross to make our approach possible; then the Holy Spirit through Whom in unity we come near in a spiritual way; then the Father, Who desires to have us before Him, in His own nature, and in relationship with Him.