(Devarim, Ibid.) "and the horns of a re'em are his horns": The strength of an ox is great, but its horns are not beautiful, whereas the horns of a re'em are beautiful, but its strength is not great. Joshua received the strength of an ox and the horns of a re'em.
"With them he shall gore peoples as one, the ends of the earth": How many peoples did Joshua conquer? How many lands did he conquer? (The meaning is) that all the Kings that he conquered ruled from one end of the world to the other.
R. Yehudah says; Now were all of the thirty-one kings that Joshua conquered in Eretz Yisrael? But just as it is with Rome now, that any king or ruler who has not acquired palaces and dependencies in Rome says "I have done nothing!" — so, every king or ruler who did not acquire palaces and dependencies in Eretz Yisrael said "I have done nothing!"