And there went out unto him all the land of Judaea, and they of Jerusalem, and were all baptized of him in the river of Jordan, confessing their sins. All the land - See on Matthew 3:4-6 (note).
Confessing their sins - It was an invariable custom among the Jews to admit no proselyte to baptism, till he had, in the most solemn manner, declared that he forever had renounced all idolatrous worship, all heathenish superstitions, and promised an entire and unreserved submission to the law of Moses. This was necessary for a proselyte adult - a child dedicated to God by baptism must be brought up in this faith.