VI. The Deity and the Manhood were present in Christ from the very first
Keep far from your hearts, dearly beloved, the poisonous lies of the devil's inspirations, and knowing that the eternal Godhead of the Son underwent no growth while with the Father, be wise and consider that to the same nature to which it was said in Adam, “You are earth, and unto earth shall you go,” it is said in Christ, “sit on My right hand.” According to that Nature, whereby Christ is equal to the Father, the Only-begotten was never inferior to the sublimity of the Father; nor was the glory which He had with the Father a temporal possession; for He is on the very right hand of the Father, of which it is said in Exodus, “Your right hand, O Lord, is glorified in power;” and in Isaiah, “Lord, who has believed our report?
And the arm of the Lord, to whom is it revealed?” The man, therefore, assumed into the Son of God, was in such wise received into the unity of Christ's Person from His very commencement in the body, that without the Godhead He was not conceived, without the Godhead He was not brought forth, without the Godhead He was not nursed. It was the same Person in the wondrous acts, and in the endurance of insults; through His human weakness crucified, dead and buried: through His Divine power, being raised the third day, He ascended to the heavens, sat down at the right hand of the Father, and in His nature as man received from the Father that which in His nature as God He Himself also gave.
Source: Sermons (New Advent)