John 1:25

Their question implied that it was inappropriate for John to baptize. The Jews practiced baptism for ritual cleansing, but in all cases the baptismal candidates baptized themselves. [Note: Carson, p. 145.] There was no precedent for John baptizing other people, and the Jews did not regard themselves as needing to repent. This was something Gentiles needed to do when they converted to Judaism. Evidently when Gentiles converted to Judaism, the males of the family underwent circumcision and all members of the family, both sexes, were baptized. [Note: Morris, p. 123.] Moreover since John was not one of the prophesied eschatological figures, he appeared to them to lack authority to do what he did.