What did one have to do to be baptised by John the Baptist?

Answer 1

The baptism of John the Baptist was a baptism of repentance for Jews. John was preparing the way for Messiah. The Jews believed that Messiah was going to set up His kingdom on earth as written in the Old Testament. Messiah was the coming King, who would defeat Israel's enemies. John was calling the Jews to repent, meaning to renew their commitment to The Law and prepare for Messiah. This made John's baptism both personal and national in nature.

To be baptized, one had to be a Jew, or prepared to convert to Judaism, to acknowledge the Law as the guiding principle for life and to submit to the coming Messiah.