Yehoshua's Question at Moshe's Passing

Chazal relate that as Moshe was about to leave this world, he told Yehoshua, "Ask me every question you have."

Yehoshua answered, "My teacher, did I ever leave you for even a short time and go elsewhere? Did you not write of me, 'He did not leave the tent'?"

At that moment his understanding was weakened, and he forgot three hundred halachos and had seven hundred doubts. All the people rose to kill him. Hashem told him that to tell him what he did not know was impossible, and that he should distract them by going to war to capture Canaan.