There are two ways in which sense John the Baptist was more than a prophet:
The Greek word perissóteron means more or greater. In Luke 3:15 and John 1:20–21 we read that the people wondered whether John might perhaps be Elijah who has returned, or even the Messiah.
In Matthew 11:10 Jesus himself explains exactly what he means by calling John
more than a prophet
in Matthew 11:9. John was not just a prophet, but was also the fulfillment of a prophecy: the prophesied herald of the Lord from Malachi 3:1 (see Matthew 10:40). In the wilderness, through John, the people could await the same one who had led Israel through the wilderness of Sinai and who would, in the end time, prepare the way to God, for the coming one was none other than the Angel of Yahweh himself.
Interpretation 1:
Jesus calls John more than a prophet (Matthew 11:9). The Greek word perissóteron means more or greater. He was no ordinary prophet. Furthermore, in Luke 3:15 and John 1:20–21 we read that the people wondered whether John might perhaps be Elijah who has returned or even the Messiah.1
Interpretation 2:
In Matthew 11:10 Jesus himself explains exactly what he had meant when he referred to John as more than a prophet
in Matthew 11:9. John was not merely a prophet, but he was in fact himself the fulfillment of a prophecy. In earlier times all kings and rulers typically each had their own herald, whose duty it was to proclaim their coming. Jesus here confirms that John is indeed the prophesied herald of the Lord from Malachi 3:1 (see Matthew 10:40).2
In the wilderness, through the herald John, the people could await the coming one—the same who once led Israel through the wilderness of Sinai and who would, in the end time, prepare the way to God. If, on the basis of John’s preaching, the people expected to see more than just a man and looked beyond the arrival of an ordinary prophet, Jesus affirms their expectation. They were right to hope for much, for the coming one is none other than the Angel of Yahweh himself.3
9 Qu'êtes-vous donc allés voir? un prophète? Oui, vous dis-je, et plus qu'un prophète.