To baptize is to wash or clean (perhaps by immersing or dipping into water) as a symbolic gesture signifying a repentance or commitment.
First, John the Baptist baptized people who repented of their sins, that is those who had remorse over their wrong actions (Mark 1:4-5).
Interestingly, Jesus (who was sinless – without fault) insisted that John baptize him prior to starting his ministry on earth (Matthew 3:13-17).
Later, Jesus had his disciples baptize his followers (John 4:2).
While John baptized with water, Jesus’ baptism was with the Holy Spirit (Mark 1:8, Luke 3:16, and Matthew 3:11).