8 Among their other sins the heretics often employ as an argument the words of the Lord, I ascend unto My Father and your Father, and My God and your God. His Father is also their Father, His God their God; therefore He is not in the nature of God, for He pronounces God the Father of others as of Himself, and His unique Sonship ceases when He shares with others the nature and the origin which make Him Son and God. But let them add further the words of the Apostle, But when He says All things are put in subjection, He is excepted Who did subject all things unto Him.
And when all things have been subjected unto Him, then shall He Himself be subjected unto Him that did subject all things unto Himself, that God may be all in all</em>, whereby, since they regard that subjection as a proof of weakness, they may dispossess Him of the virtue of His Father's nature, because His natural infirmity subjected Him to the dominion of a stronger nature. And after that, let them adopt their very strongest position and their impregnable defence, before which the truth of the Divine birth is to be demolished; namely, that if He is subjected, He is not God; if His God and Father is ours also, He shares all in common with creatures, and therefore is Himself also a creature: created of God and not begotten, since the creature has its substance out of nothing, but the begotten possesses the nature of its author.
Source: On the Trinity (New Advent)