“And Jesus, when he was baptized, went up straightway out of the water: and, lo, the heavens were opened unto him, and he saw the Spirit of God descending like a dove, and lighting upon him:”
And when Jesus was baptized, immediately he went up from the water, and behold, the heavens were opened to him, and he saw the Spirit of God descending like a dove and coming to rest on him. The baptism of Jesus produces a theophany — a visible divine manifestation. The opened heavens is the language of prophetic vision (Ezekiel 1:1; Isaiah 64:1 asking God to tear open the heavens and come down). The Spirit descending like a dove echoes the Spirit hovering over the waters of creation in Genesis 1:2 — the new creation is beginning at the Jordan. The dove that returned to Noah with an olive branch signaling the end of judgment (Genesis 8:11) now descends on Jesus signaling the end of the old age and the beginning of the new. Anointing with the Spirit is the initiation of royal and prophetic ministry (1 Samuel 16:13; Isaiah 61:1).
Church Fathers on Matthew 3:16
For, as we have said, when the Saviour was washed, then the water was cleansed for our baptism, that a laver might be ministered to the people who were to come. Moreover, it behoved that in Christ’s baptism should be signified those things which the faithful obtain by baptism.
This action of Christ’s has a figurative meaning pertaining to all who were after Him to be baptized; and therefore he says, 'straightway He ascended,' and not simply 'He ascended,' for all who are worthily baptized in Christ, straightway ascend from the water; that is, make progress in virtues, and are carried on towards a heavenly dignity. They who had gone down to the water carnal and sinful sons of Adam, straightway ascend from the water spiritual sons of God. But if some…
As by the immersion of His body He dedicated the laver of baptism, He has shewn that to us also, after baptism received, the entrance to heaven is open and the Holy Spirit is given, as it follows, 'and the heavens were opened.'