John 17:3

3. Life eternal… might know thee This knowing of God and Christ is that full experimental knowing which, being commenced by the believer on earth, is consummated in eternity: hence it is not the cause of eternal life, but is the very eternal life itself. The vital seed of eternal life, its first minute instalment, is placed within the believing soul on earth, and, unless on earth removed, will put forth in eternal life in heaven. It is the well of water within springing up to everlasting life.

The only true God The only God; for there can be no other. The true God, in opposition to all false gods. Whether Jupiter, or Brahm, or Vishnu, they are false. The fancies of the idolater, of the pantheist, or the atheist, have their absolute contradiction in this the true God. He possesses those attributes of power, wisdom, and mercy; he has unfolded those attributes in such plans and deeds of redemption, as that eternal life is realized in the very knowing them in their knowable fulness.

And Jesus Christ It is remarkable that this is the only instance in the Gospels in which the words Jesus Christ are used as one compound name. They are so used frequently in the Epistles; from which some liberalistic commentators have argued that this phrase was mistakenly used by John, according to a later custom, and falsely attributed by him to Christ. More likely, however, the apostolic custom arose in the Epistles from its original use by Jesus. It is a most expressive compound. Jesus is Saviour: Christ is Messiah; that is, Anointed King. Hence Jesus Christ is Saviour-Messiah, Saviour-King. He is a Royal Saviour sent from God to man. It is with a solemn majesty that Jesus thus pronounces his compound name of dignity, naming himself thus before God and man.

Unitarian writers, who deny the divinity of Jesus Christ, have quoted this as a primary text to show that Christ is not God, but purely man. God, as they claim, is pronounced here to be sole God, and Jesus Christ is excluded. But surely it is of that very sole God that Jesus Christ is the Sent, the manifestation, the incarnation. The Father, indeed, as the unknowable Absolute, the reserve of Deity, is often styled by the entire name of God.

So the very first verse of John’s Gospel tells us that the Word was with God; that is, with the Father. But that did not forbid his adding, “and the Word was God.” And so, that the Father is God does not disprove that Jesus Christ is God manifest in the flesh.