Musnad Ahmad 30:3547

Rawh narrated to us, Awf narrated to us, from al-Hasan, from the Prophet (peace and blessings of Allah be upon him), and Khilas and Muhammad, from Abu Hurayrah, from the Prophet (peace and blessings of Allah be upon him), that he said regarding this verse: "O you who have believed, be not like those who annoyed Moses; then Allah cleared him of what they said" [Al-Ahzab: 69]. He said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, Moses was a shy, concealing man; almost nothing of his skin could be seen due to his shyness. He said: So those who annoyed him from the Children of Israel annoyed him. They said: 'This one does not conceal himself in this manner except because of a defect in his skin, either leprosy or a scrotal hernia'—and Rawh said: 'Sometimes a hernia, or some ailment'—and indeed Allah, the Mighty and Majestic, wanted to clear him of what they said. And indeed, Moses was alone one day, so he placed his garment upon a stone, then he bathed. When he finished, he came toward his garment to take it, but the stone ran off with his garment. Moses took his staff and pursued the stone, and he began saying: 'My garment, O stone! My garment, O stone!' until he reached a gathering of the Children of Israel. They saw him naked, as the best of men in creation, and He cleared him of what they were saying about him. The stone stood still, so he took his garment and began striking the stone with his staff. He said: By Allah, there are indeed scars on the stone from the effect of his striking it three, or four, or five times."