Musar do Liczb 13:31

And now we shall explain in brief the episode of the spies. For, on the surface, it is cause for great wonder: What is it that caused them to sink to such depths and to mislead Israel? More than that — even Sanhedrin erred in this, it being written (Bamidbar 19:1): "And the entire congregation [the Sanhedrin (Rashi)] lifted their voices, etc." And more than this, they said (Ibid. 13:31): "For they are stronger than He," which our sages of blessed memory interpreted as: "He is unable, as it were, to rescue His vessels from there." How could they speak such nonsense?

(Ibid. 13:31): "And the men who went up with him said: 'We shall not be able to go up against the people [(that is, we will not even be able to go up, as they said before (30): "Amalek dwells in the land of the south, and the Chitti, etc.")], for they are stronger than He.'" That is, when does the Holy One Blessed be He drive out a people? When He finds another that is better than it, He gives them power to destroy them and to inherit their place. But for people such as we, who were great sinners with the golden calf and with the flesh of lust, He will not drive out such great peoples. As to His promising us to give us the land, this is only on condition that we merit it, as tzaddikim. [Then,] He would drive out the foe before us and would grant us permission to destroy them.