Matteo 3:15

So Jesus overrules John's objection: And Jesus, answering, said unto him, Suffer it to be so now; for thus it becometh us to fulfill all righteousness. Then he suffered Him.

Obedience and fulfillment were the outstanding traits of the Messiah's vicarious work. In applying these, He could brook no opposition. Every righteous ordinance, all religious usages that were enjoined upon the people. He wanted to fulfill. This Jesus gently, but firmly urged. It was the proper, the right, and the expedient thing to do. And so John acquiesced.

From ancient times the teachers of the Church have found here a wider, larger reference. "Jesus says:... If that shall be performed that the poor sinners may come to righteousness and be saved, you must baptize Me. Because for the sake of sinners I have become a sinner, must therefore do what God has charged the sinners to do, in order that they may become just through Me."