Great is "song," which obtains in the past, and obtains in the future, and obtains in time to come (the time of the Messiah) and obtains in the world to come.
(Devarim 32:44) "And Moses came": It is written here "And Moses came," and elsewhere, (Ibid. 31:1) "And Moses went." It cannot be said "And Moses came," for it is already said "And Moses went"; and it cannot be said "And Moses went," for it is already said "And Moses came." It must be understood, then, as: His time came to an end and his authority was given to another (Joshua).