32 These are the steps by which He advances the knowledge of Himself. He teaches that He has come out from the Father, proclaims that the Father is with Him, and testifies that He has conquered the world. He is to be glorified of the Father, and will glorify Him: He will use the power He has received, to give to all flesh eternal life. Then hear the crowning point, which concludes the whole series, And this is life eternal, that they should know You, the only true God, and Him Whom You sent, even Jesus Christ. Learn, heretic, to confess, if you cannot believe, the faith which gives eternal life. Separate, if you can, Christ from God, the Son from the Father, God over all from the true God, the One from the Only: if, as you say, eternal life is to believe in one only true God without Jesus Christ. But if there is no eternal life in a confession of the only true God, which separates Christ from Him, how, pray, can Christ be separated from the true God for our faith, when He is not separable for our salvation?
Source: On the Trinity (New Advent)