"Thus says the LORD: Here is my servant whom I uphold, my chosen one with whom I am pleased, upon whom I have put my spirit; he shall bring forth justice to the nations" -Is 42:1-4, 6-7
Jesus Christ is the chosen one of God. In Him the Father is well pleased. Why does He use the sign of repentance in baptism through the ministry of John?
In our liturgy this Sunday we celebrate the feast of the Baptism of the Lord. Although he had no need to repent, being sinless, Christ submitted to the sign of repentance through baptism by John to show that through His Passion, death and Resurrection we now have the means to repent, to be found pleasing to the Father because of Him.
“The baptism of Jesus is on his part the acceptance and inauguration of his mission as God's suffering Servant. He allows himself to be numbered among sinners; he is already "the Lamb of God, who takes away the sin of the world". Already he is anticipating the "baptism" of his bloody death. Already he is coming to "fulfill all righteousness", that is, he is submitting himself entirely to his Father's will: out of love he consents to this baptism of death for the remission of our sins. The Father's voice responds to the Son's acceptance, proclaiming his entire delight in his Son. 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" - the heavens that Adam's sin had closed - and the waters were sanctified by the descent of Jesus and the Spirit, a prelude to the new creation.” (CCC 536)