When Moses was about to enter Paradise he turned to Joshua and said, "If
any doubtful matters remain, ask me now and I will explain them." To
this Joshua replied, "Have I ever left thy side for an hour and gone
away to any other? Hast thou not thyself written concerning me (Exod.
xxxiii. 11), 'His servant Joshua, the son of Nun, a young man, departed
not out of the Tabernacle?'" As a punishment for this pert reply, which
must have distressed and confounded his master, Joshua's power of brain
was immediately weakened, so that he forgot three hundred Halachahs, and
seven hundred doubts sprang up to perplex him. All Israel then rose up
to murder him, but the Holy One--blessed be He!--said unto him, "To
teach thee the Halachahs and their explanation is impossible, but go and
trouble them with work; as it is said (Josh. i. 1), 'Now after the death
of Moses, the servant of the Lord, it came to pass that the Lord spake
unto Joshua,'" etc.
THE TALMUD, _Temurah_, fol. 16, col. 1.