The Messenger of Allah (peace and blessings be upon him) said: "The Children of Israel used to bathe naked, looking at one another's private parts, while Musa (peace be upon him) used to bathe alone. They said: 'By Allah, Musa (peace be upon him) does not bathe with us only because he has some ailment.' Once he (peace be upon him) went to bathe and placed his clothes on a stone, and the stone ran off with his clothes. Musa (peace be upon him) ran after it, saying: 'Thawbi hajar, thawbi hajar' (My clothes, O stone! My clothes, O stone!), until the Children of Israel looked at the private parts of Musa (peace be upon him) and said: 'By Allah, there is nothing wrong with Musa (peace be upon him).' After they had looked at him, the stone stood still, so he took his clothes and began to strike the stone." Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: By Allah, there were six or seven marks on the stone from the beating of Musa (peace be upon him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 959