In the introduction to Jesus of Nazareth, Pope Benedict comments at some length on Deuteronomy 18 and 34, the first of which contains the promise that a prophet like Moses will arise and the second of which reflects that “there has not arisen a prophet since in Israel like Moses, whom the Lord knew face to face.” The Pope focuses on this verse because he bases his entire book on the relationship of Jesus to the Father: Jesus is greater than all prophets because he speaks on the basis of seeing face to face (cf. pg. 5).
The argument is this: Moses promised that a prophet like him will arise, and commands that Israel should listen to that prophet. But since chapter 34, presumably written long after Moses’ death and long after other true prophets have spoken in Israel, says that no prophet like Moses has arisen, we can conclude that Moses did not mean to promise in a generic way that there would be real prophets but in a specific way that there would be some individual prophet uniquely like Moses. Since no such prophet has arisen, the promise must have to do with a future savior, the Messiah.
A wrinkle in this argument is that Elijah is strongly portrayed as like Moses in 1Kings. His trip of forty days and forty nights leads him to the very mountain on which Moses saw God, and there he indeed speaks with God directly. If we date Deut. 34 to near the time of the exile, as most moderns do, then it discounts even Elijah as the prophet like Moses and so the argument still holds. (It is interesting, by the way, that Elijah is the most likely OT candidate for fulfilling the prophecy of Deut. 18, since in the gospels the strongest “runner-up” for Messiah is John the Baptist–whom Jesus identifies as Elijah!)
But a more general solution may also work. I would argue that the interplay between Deut. 18 and Deut. 34 is a good example of the developing tradition described on pgs.20-21. The promise in Deut. 18 could initially have been a general description of the institution of the true prophet in Israel, with “like me” pointing to the difference between Israelite and pagan prophets generally. But putting the difference that way cast a tension into the very office of prophet: to be a prophet in Israel, one must be measured by a standard one can never meet, namely “like Moses”–like Moses, the human founder of the entire nation. No one could possibly match that description fully until he brought about a new exodus!
So Deut. 34, whether written before or after Elijah, shows that Israel was beginning to see how much had been packed into that earlier promise: no one yet has measured up. So one could make a reasonable case that any true prophet is “like Moses”; one could make an even better case that Elijah was “like Moses”; but the tension will remain until the full potential of those words is exhausted, and Israel freed.

