42 The words of the Apostle's faith are a barrier against your reckless and frenzied profanity, which forbids you to turn the freedom of speculation into licence, and wander into error. Every tongue, he says, shall confess that Jesus is Lord in the glory of God the Father. The Father has glorified Him in Himself, therefore He must be confessed in the glory of the Father. And if He is to be confessed in the Father's glory, and the Father has glorified Him in Himself, is He not plainly all that His Father is, since the Father has glorified Him in Himself and He is to be confessed in the Father's glory?
He is now not merely in the glory of God, but in the glory of God the Father. The Father glorifies Him, not with a glory from without, but in Himself. By taking Him back into that glory, which belongs to Himself, and which He had with Him before, the Father glorifies Him with Himself and in Himself. Therefore this confession is inseparable from Christ even in the humiliation of His manhood, as He says, And this is eternal life, that they should know You, the only true God, Him, Whom You sent, even Jesus Christ; for firstly there is no life eternal in the confession of God the Father without Jesus Christ, and secondly Christ is glorified in the Father.
Eternal life is precisely this, to know the only true God and Him, Whom He sent, even Jesus Christ; deny that Christ is true God, if you can have life by believing in God without Him. As for the truth that God the Father is the only true God; let this be untrue of the God Christ, unless Christ's glory is wholly in the only true God the Father. For if the Father glorifies Him in Himself, and the Father is the only true God, Christ is not outside the only true God, since the Father, Who is the only true God, glorifies in Himself Christ, Who is raised into the glory of God. And in that He is glorified by the only true God in Himself, He is not estranged from the only true God, for He is glorified by the true God in Himself, the only God.
Source: On the Trinity (New Advent)