But why did Jesus, in whom there is no shadow of sin, go to be baptized by John? Why did he perform that gesture of penitence and conversion, beside all those people who in this way were trying to prepare for the coming of the Messiah? That gesture — which marks the start of Christ’s public life — comes in continuity with the Incarnation, the descent of God from the highest heaven into the abyss of hell. The meaning of this movement of divine lowering is expressed in a single word: love, the very name of God. The Apostle John writes: “In this the love of God was made manifest among us, that God sent his only Son into the world, so that we might live through him”, and he sent him “to be the expiation for our sins” (1 Jn 4:9-10). That is why the first public act of Jesus was to receive baptism from John, who, seeing him approaching, said: “Behold, the Lamb of God, who takes away the sin of the world” (Jn 1:29).
Luke the Evangelist recounts that while Jesus, having received baptism, “was praying, the heaven was opened, and the Holy Spirit descended upon him in bodily form, as a dove, and a voice came from heaven, ‘Thou art my beloved Son; with thee I am well pleased’” (3:21-22). This Jesus is the Son of God who is totally immersed in the will of the Father’s love. This Jesus is the One who will die on the cross and rise again through the power of the same Spirit who now descends upon him and consecrates him. This Jesus is the new man who wills to live as the son of God, that is, in love; the man who in the face of the evil of the world, by choosing the path of humility and responsibility he chooses not to save himself but to offer his own life for truth and justice. Being Christian means living like this, but this kind of life involves a rebirth: to be reborn from on high, from God, from Grace. This rebirth is the Baptism, which Christ gives to the Church in order to regenerate men and women to new life. An ancient text attributed to St Hippolytus states: “Whoever goes down into these waters of rebirth with faith renounces the devil and pledges himself to Christ. He repudiates the enemy and confesses that Christ is God, throws off his servitude, and is raised to filial status” Discourse on the Epiphany, 10: PG 10, 862).
[Pope Benedict, Angelus, 13 January 2013]