Matthew 3:11 (NASB)
He will baptize you with the Holy Spirit and fire.
Fire has many cleansing properties. It burns away the dross and impurities. It also provides heat, warmth, light, and comfort. A child of God baptized in the Holy Spirit demonstrates conviction, boldness, and certainty that stuns the world. When the Jews saw the eloquence and courage of Peter and John, they realized that they were with Jesus (Acts 4:13). A fire burns away chaff and lays bare the ground. The fire of the Holy Spirit cleanses the innermost being of a man's soul, laying everything bare in the sight of God (Hebrews 4:12-13). When the Holy Spirit convicts a man, his immediate reaction could be repentance (Luke 5:8) or worldly sorrow leading to damnation (Matthew 27:4). The arrival of the cleansing fire of the Holy Spirit in a man also changes him physically. He can endure temptations, hunger, and suffering (Matthew 4:1-3). His countenance becomes determined and brave, and his face is like chiseled granite (Luke 9:51). Ultimately, that soul is regenerated and grows in love, holiness, and the fruit of the Spirit (Galatians 5:22-23). John's water baptism leads to repentance, but ultimately, the baptism of fire in the Holy Spirit sets us heavenward.