33 I know that laboured solutions of difficult questions do not find favour with the reader, but it will perhaps be to the advantage of the faith if I permit myself to postpone for a time the exposition of the full truth, and wrestle against the heretics with these words of the Gospel. You hear the statement of the Lord, This is life eternal, that they should know You, the only true God, and Him Whom You sent, even Jesus Christ. What is it, pray, which suggests to you that Christ is not the true God? No further indication is given to show you what you should think of Christ. There is nothing but Jesus Christ: not Son of Man, as He generally called Himself: not Son of God, as He often declared Himself: not the living bread which comes down from Heaven, as He repeated to the scandal of many. He says, You, the only true God, and Him Whom You sent, even Jesus Christ, omitting all His usual names and titles, natural and assumed. Hence, if the confession of the only true God, and of Jesus Christ, gives us eternal life, without doubt the name Jesus Christ has here the full sense of that of God.
Source: On the Trinity (New Advent)