Mark 1:4

4 John did baptize in the wilderness, and preach the baptism of repentance for the remission of sins.

Ver. 4. John did baptize in the wilderness ] Like as at the promulgation of the law, the people were commanded to wash their garments, and sanctify themselves; so at the first publication of the Gospel, to wash their hands, and cleanse their hearts; and in testimony or profession thereof, to believe and be baptized for remission of sins.