Even from the moment of his conception he was the Son of God (by nature), he had no sin, he was filled with the perfection of all the gifts and virtues (as well as of all knowledge), his human soul was indeed that place where the fullness of Godhead deigned to dwell.
Jesus obviously could not increase in grace, being perfect from the moment of his conception
he was redeemed by the offering of a pair of turtle doves or two young pigeons – however, he most certainly did not need to be redeemed by any ritual sacrifice, being wholly pure and undefiled in himself.
his baptism was not for his own sake, or for an increase in grace in himself, but (like everything in his life) it was offered for our benefit, and for the glory of his Father through the salvation of men.
the end of grace is the union of God with man – but this union was effected perfectly in Christ through the hypostatic union of the divine essence with his true human nature.
there is simply and absolutely no union between God and man which could be greater than the union of humanity and divinity in the single person of our Savior, it is quite obvious that there could be no absolute increase in grace in our Lord from the first moment of his conception.
our Lord enjoyed the beatific vision from the first moment of his conception
because the beatific vision is the greatest grace which a man may enjoy, from this it is obvious that our Lord could not increase in grace but was perfected in all grace from the beginning of his existence as man.
The heavens were opened as a sign for our benefit, for the baptism of Christ is a cause of grace in us.
Aquinas (that is, the Angelic Thomas) gives three reasons: 1) To show that it is a heavenly power which sanctifies baptism and effects the grace of baptism in all those who are baptized. 2) Baptism is the “door of faith”, by which faith we gaze upon the things of heaven. 3) Finally, heaven is closed to us before we are baptized. Thus, because baptism is the opening for us to the way to heaven, the heavens were opened as a sign for us at the baptism of our Savior.
the faithful after baptism stand in need of prayer. Or else, that we may be led to understand that the very fact that through baptism heaven is opened to believers is in virtue of the prayer of Christ.
