John the Baptist.
v.1-2 In those days (c. 28 A.D.), John the Baptist came preaching in the wilderness of Judea “Repent, for the kingdom of heaven is at hand.” Here, repent means a radical turn around of your mind and action.
v.3 John fulfilled prophecy (Is 40:3): “The voice of one crying in the wilderness: ‘Prepare the way of the Lord; make his paths straight.’”
v.4 John wore a garment made of camels hair, the typical clothing for a desert nomad and associated with poor people. Desert locusts were food for the poor and are still eaten by the poor in the Middle East today. The clothing and food establish a linkage to the OT prophet Elijah (2 Kgs 1:8, Mal 4:5).
v.5-6 John was a charismatic figure who drew great crowds from the surrounding areas (which are personified in the text). The people confessed their sins and were baptized, in the Jordan river, as an outward symbol of turning from sin. Josephus states that John required righteous conduct as a prerequisite to baptism if it is to be acceptable to God (Antiquities 18.v.2).
v.7-10 John warns the Pharisees and Sadducees that they must bear fruit in keeping with repentance and not just rely on having Abraham as their father. Any tree that does not bring forth good fruit will be cut down and destroyed.
v.11-12 John’s water baptism is to be superseded by the coming Messiah who will baptize with the Holy Spirit and fire. The fire in verse 11 is purifying and in verse 12 destroying. Christ’s work divides people into two camps the chaff (unrepentant) and the wheat (children of the kingdom).

Read Matthew 3:1-12