Jesus Begins His Ministry with a Reference to the Trinity

St. Ambrose: Scripture speaks of Jesus himself as God and man, perfect in both natures. It speaks of the Father and the Holy Spirit. For the Holy Spirit is shown as Christ’s partner when he descends in bodily shape as a dove on Christ, when the Son of God was baptized in the river, and when the Father spoke from heaven. So what greater testimony to us who are weak than that Christ signified with his own voice that he himself spoke by the prophets? Exposition on the Gospel of Luke 4.44-45