Now that we have passed Epiphany, the day on which we celebrate the visit of the Wise Men to the Christ Child, signifying the extension of Christ's salvation to the Gentiles, the next stop on the liturgical calendar is the feast of the Baptism of the Lord. Traditionally, this feast was celebrated on the octave day (eighth day) of Epiphany (that is, January 13), but now it is celebrated on the Sunday after Epiphany, unless the celebration of Epiphany has been transferred to that Sunday, in which case the Baptism of the Lord is celebrated on the next day. (See When Is Epiphany? for more details on the transfer of the celebration of Epiphany and When Is the Baptism of the Lord? for the date on which the Feast of the Baptism of the Lord is celebrated each year.)
Since the Catholic Church teaches that the Sacrament of Baptism is necessary for the remission of sins, particularly Original Sin, why was Christ baptized? After all, He was born without Original Sin, and He lived His entire life without sinning. Therefore, He had no need of the sacrament, as we do.
In submitting Himself humbly to the baptism of St. John the Baptist, however, Christ provided the example for the rest of us. If even He should be baptized, though He had no need of it, how much more should the rest of us be thankful for this sacrament, which frees us from the darkness of sin and incorporates us into the Church, the life of Christ on earth? His Baptism, therefore, was necessary--not for Him, but for us.
Many of the Fathers of the Church, as well as the medieval Scholastics, saw Christ's Baptism as the institution of the sacrament. His Flesh blessed the water, and the descent of the Holy Spirit (in the form of a dove) and the voice of God the Father announcing that this was His Son, in Whom He was well pleased, marked the beginning of Christ's public ministry.
More on the Baptism of the Lord:
(A Russian icon of the Baptism of the Lord in the River Jordan by St. John the Baptist. The dove represents the Holy Spirit; the three angels represent the Trinity. Photo © Slava Gallery, LLC; used with permission)