Mark 1:4, 7

John the Baptist appeared in the wilderness preaching a baptism of repentance for the forgiveness of sins [that is, requiring a change of one’s old way of thinking, turning away from sin and seeking God and His righteousness].

And he was preaching, saying, “After me comes He who is mightier [more powerful, more noble] than I, and I am not worthy to stoop down and untie the straps of His sandals [even as His slave].