The Baptism of the Lord - Feast - Year C
"Then the heavens opened and the Holy Spirit descended on Jesus"
If it is said that Christ received the Holy Spirit this is because he had become man and it was fitting for man to receive it. Undoubtedly he is Son of God the Father and begotten of his substance, both before the Incarnation and even before all ages. In spite of this there was no sadness in him when he heard the Father say to him once he became man: “You are my Son, today I have become your Father.”
He who was God, begotten before all ages, the Father says to have been begotten today. This means that he receives us into himself as adopted children, for all humanity was contained in Christ in that he was man. In this sense one might say that the Father, while his Son already possessed the Spirit, gives it to him once again in such a way that we might receive the gift of the Spirit in him. Christ did not receive the Holy Spirit for himself alone but rather for us who were in him. For it is through him that all good things come to us.
Saint Cyril of Alexandria (380-444), Bishop, Doctor of the Church