Even though Matthew has not recorded any previous interaction between Jesus and John (remember to read Matthew according to Matthew, not Luke), John knows who Jesus is. And he doesn’t want to baptize Him, or, he knows there is no reason to baptize Jesus. John’s baptism was a sign of repentance and Jesus had nothing to repent, therefore he did not need to be baptized. Jesus’ reply is the key to the passage, even more important than the Trinitarian convergence we read of following the baptism. Jesus’ purpose was to “fulfill all righteousness.” He was baptized to show his identity with the sinners, and then to give to them His righteousness. He became one of us, yet did so without sinning, so that we could become like Him – righteous or perfect in the eyes of God.
That’s what happened in our baptism – Jesus gave us His ‘robe of righteousness.’ Because of His perfection, we are seen as perfect in God’s eyes. Thank God for His perfect grace given to us through His perfect Son!