People thought John the Baptizer was someone great, and he was, but he explained to people that he did not even begin to approach in greatness the One who was coming next,
“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 3:11-12).
John merely used water to baptize people, and so he was not even worthy to carry the sandals of the next Man who was coming, because that Man would baptize people in the Holy Spirit and in fire.
Please note that the Holy Spirit and fire are not the same thing, for John explained in verse 12 that the fire to which he referred was hellfire.
The coming Great One would baptize some people in the Holy Spirit, and baptize others in fire, both of which are greater than the water in which John baptized.
If John paled in comparison to the One who was coming, then all people likewise fade in glory in comparison to the One who baptizes in the Holy Spirit and fire.