What did John the Baptist preach?

John the Baptist's core message centered on repentance and the coming of Christ, who would baptize with the Holy Spirit. His ministry called for a turning away from sin toward faith in the one to come, illustrating that true repentance is a response to God's grace already at work in the heart. John declared that forgiveness of sins was available through the blood of Christ, highlighting both personal depravity and the need for divine salvation. His preaching established the foundation for the subsequent ministry of Jesus, who fulfilled the promise of redemption.