Musnad Ahmad 30:1182

'Abd al-Samad narrated to us, my father narrated to me, al-Jurayri narrated to us, from 'Abd Allah ibn Shaqiq, who said: I stayed in Medina with Abu Hurayrah for a year. One day, while we were at the chamber of 'A'ishah, he said to me: "I have seen us when we had no clothes except for tattered cloaks. Days would pass for one of us without finding food to sustain his spine, to the point that one of us would take a stone and tie it against the hollow of his stomach, then bind it with his garment to sustain his spine." "One day, the Messenger of Allah (peace and blessings of Allah be upon him) distributed dates among us, and each of us received seven dates, among which was a shriveled one. I was not pleased that I had a good date in its place." I asked: "Why?" He said: "It would have been more substantial for my chewing." He then said to me: "Where have you come from?" I said: "From al-Sham." He said: "Have you seen the stone of Moses?" I said: "And what is the stone of Moses?" He said: "The Children of Israel said something to Moses regarding his private parts beneath his clothes. So, he placed his clothes on a rock while he was bathing, and it (the rock) ran off with his clothes. He followed it, saying: 'O stone, return my clothes! O stone, return my clothes!' until it brought him to the Children of Israel, who saw him perfect and well-formed, and it had three marks (or bruises) on it." "By the One in Whose hand is the soul of Abu Hurayrah, if you had looked, you would have seen the marks of Moses upon it."