It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him), who says: A man who is better and superior to me narrated to me—by this he meant Sayyiduna Abu Qatadah Salmi Ansari (may Allah be pleased with him)—he narrated that Sayyiduna Ammar bin Yasir (may Allah be pleased with him) was digging the trench, and the Messenger of Allah (peace and blessings be upon him) was brushing the dust from his head and saying: "Alas for the calamity of the son of Sumayyah! (O Ammar!) A rebellious group will kill you."