“After the Lord was baptized, the heavens were opened, and the Spirit descended upon him like a dove, and the voice of the Father thundered: This is my beloved Son, with whom I am well pleased.” (Entrance Antiphon ~ Cf. Mt 3: 16-17, Daily Roman Missal)

The Spirit whom Jesus possessed in fullness from his conception comes to “rest on him”. Jesus will be the source of the Spirit for all mankind. At his baptism “the heavens were opened”… (CCC 536)