Комментарий к Дварим 1:42

לא תעלו “GO NOT UP” — There will be no “ascent” for you, but only a descent (defeat) (cf. Rashi on Numbers 16:12 and Numbers Rabbah 17:3).

There will be no going up [victory] for you etc. Since it is written, “Do not go up,” why then does it need to say, “Do not wage war”? It is obvious that if they do not go up, then there will be no war. Rather, the verse must certainly mean: “Do not go up, for you will not be able to wage war against them.” And if so, going up [the mountain] will be your downfall. But Re”m explains: Since it is written, “So that you will not be shattered,” we can infer that the statement, “Do not go up,” is intended for their benefit. If so, it is not a warning. Rather, it is informing them that their course of action will not be victorious, etc.