After these things, Jesus came with his disciples into the land of Judea. He stayed there with them, and baptized.
This taking a hand in the preaching of baptism, on the part of Jesus, was probably the result of our Lord's having seen the urgent need in his interview with Nicodemus.  With the blindness of the religious leaders in their rejection of John the Baptist's preaching, it was clear that John needed all the help he could get; therefore, Jesus encouraged his disciples to take a hand in the baptizing.  The connection of John's baptism (so-called) with the kingdom of heaven lies in the fact of its being the only baptism submitted to by the Lord's disciples prior to Pentecost; for all such, it was not necessary for them to be baptized again, but only to receive the Holy Spirit, thus completing in them the new birth.  After Pentecost, the old baptism was no longer valid, but was replaced by the baptism of the great commission.