Baptism of the Lord, Giotto, circa 1305
Why did Jesus need to be baptized?
John the Baptist appears to recognize the strangeness of Jesus asking to be baptized (Matt. 3:14) yet obeys Jesus' request.
The baptism of Jesus began his public ministry and gave the first example that we are to follow. For if Jesus, who had no need of repentance or cleansing, humbled himself, then we all the more need to humble ourselves.
Jesus not only gave the example for us to follow, but many Fathers of the Church commented that in the baptism of Jesus the sacrament of baptism was born. It was a symbolic action that, though the grace of Christ, was changed into an ontological action. When we receive a sacrament, the grace flows to us from the sacrament, but in the baptism of Jesus the grace of Christ flowed into the sacrament.
In salvation history, the Jordan River was very important. It was through the Jordan River that Joshua led the Israelites into the Promised Land. Jesus chose this spot to be baptized so that through his immersion and emergence from the Jordan River all humanity could be led to heaven.
Ultimately, the reason Jesus chose to be baptized in the Jordan by John was not for him but for us.
From: Catholic.com
A Sermon by St Gregory Nazianzen
The Baptism of Christ
Christ is bathed in light; let us also be bathed in light. Christ is baptized; let us also go down with him, and rise with him.
John is baptizing when Jesus draws near. Perhaps he comes to sanctify his baptizer; certainly he comes to bury sinful humanity in the waters. He comes to sanctify the Jordan for our sake and in readiness for us; he who is spirit and flesh comes to begin a new creation through the Spirit and water.
The Baptist protests; Jesus insists. Then John says: I ought to be baptized by you. He is the lamp in the presence of the sun, the voice in the presence of the Word, the friend in the presence of the Bridegroom, the greatest of all born of woman in the presence of the firstborn of all creation, the one who leapt in his mother’s womb in the presence of him who was adored in the womb, the forerunner and future forerunner in the presence of him who has already come and is to come again. I ought to be baptized by you: we should also add, “and for you,” for John is to be baptized in blood, washed clean like Peter, not only by the washing of his feet.
Jesus rises from the waters; the world rises with him. The heavens, like Paradise with its flaming sword, closed by Adam for himself and his descendants, are rent open. The Spirit comes to him as to an equal, bearing witness to his Godhead. A voice bears witness to him from heaven, his place of origin. The Spirit descends in bodily form like the dove that so long ago announced the ending of the flood and so gives honour to the body that is one with God.
Today let us do honour to Christ’s baptism and celebrate this feast in holiness. Be cleansed entirely and continue to be cleansed. Nothing gives such pleasure to God as the conversion and salvation of men, for whom his every word and every revelation exist. He wants you to become a living force for all mankind, lights shining in the world. You are to be radiant lights as you stand beside Christ, the great light, bathed in the glory of him who is the light of heaven. You are to enjoy more and more the pure and dazzling light of the Trinity, as now you have received – though not in its fullness – a ray of its splendour, proceeding from the one God, in Christ Jesus our Lord, to whom be glory and power for ever and ever. Amen.