Question:Please explain the "baptism of fire." Thank you.
The concept of a baptism of fire comes from a statement made by John the Baptist. "And even now the ax is laid to the root of the trees. Therefore every tree which does not bear good fruit is cut down and thrown into the fire. I indeed baptize you with water unto repentance, but He who is coming after me is mightier than I, whose sandals I am not worthy to carry. He will baptize you with the Holy Spirit and fire. His winnowing fan is in His hand, and He will thoroughly clean out His threshing floor, and gather His wheat into the barn; but He will burn up the chaff with unquenchable fire" (Matthew 3:10-12 and also in Luke 3:16-17). This is the only time the concept of baptism is connected with fire.
From the full statement we see that fire here deals with the separation of the just from the wicked and the eternal punishment of the wicked. The baptism with the Holy Spirit is for the just, but the baptism in fire is for the wicked. Basically John is stating that he, as a prophet of God, was given authority to convert people. But Jesus would be greater than he because Jesus has the authority to both convert people and to destroy the unconverted. "And do not fear those who kill the body but cannot kill the soul. But rather fear Him who is able to destroy both soul and body in hell" (Matthew 10:28).