Silsilat al-Ahadith al-Sahihah

Sayyiduna Ammar bin Yasir (may Allah be pleased with him) says: I and Sayyiduna Ali (may Allah be pleased with him) were companions in the expedition of Dhu al-‘Ushayrah. When the Messenger of Allah (peace and blessings of Allah be upon him) camped there and stayed, we saw some people from the tribe of Banu Mudlij working in one of their date-palm springs. Sayyiduna Ali (may Allah be pleased with him) said to me: Abu al-Yaqzan! What do you think, should we go to them and see how they work? So we went to them and watched their work for a while, then sleep overcame us. I and Sayyiduna Ali (may Allah be pleased with him) went into a cluster of date-palms and lay down in the soil and slept. By Allah! The Messenger of Allah (peace and blessings of Allah be upon him) woke us up by moving us with his foot, and we were covered in dust from the soil. When the Messenger of Allah (peace and blessings of Allah be upon him) saw the dust on Sayyiduna Ali (may Allah be pleased with him), he said: “O Abu Turab! (i.e., the man of dust).” Then he (peace and blessings of Allah be upon him) said: “Shall I not tell you about the two most wretched men?” We said: O Messenger of Allah! Why not. He (peace and blessings of Allah be upon him) said: “The red one of Thamud, who hamstrung the she-camel, and the man who (O Ali!) will strike your head until your (beard) is soaked with blood.”

Abdullah bin Anas reports Mursal that the Prophet Muhammad (peace be upon him) said: "Among the people of old, the most wretched was the one who hamstrung (the she-camel of Sayyiduna Salih as a miracle), and O Ali! Among the latter ones, the most wretched will be the one who strikes you with a spear." Then the Prophet (peace be upon him) also pointed towards the place of the spear wound.