The Prophet mentioned Deuteronomy 18:15. Some think that the Jews expected an eminent prophet, besides Elias, to come before the Messiah; and 1 Thessalonians 1:21 would incline us to think so. But others say, it cannot be proved from their writers, that they had any expectations of any but Elias and the Messiah. But the words may be read as well, this is a prophet, as this is the prophet; and I think that is the true sense of them. A prophet had now for more than four hundred years been a great rarity amongst them, they having had none but John the Baptist who had such a repute.
Related Commentaries of John 7:40
John 7:40
40 Many of the people therefore, when they heard this saying, said, Of a truth this is the Prophet.