Abu Qatada told that when `Ammar was digging the trench God's messenger began to wipe his head and say, "How unfortunate Ibn Sumayya is! The wicked party will kill you[*]."
*Yasir, 'Ammar's father, is said to have come from the Yemen to Mecca, where he married a slave woman called Sumayya who bore 'Ammar. `Ammar fought on 'Ali's side at the battle of Siffin (37 A.H.) and was killed. The wicked party mentioned in the tradition is Mu'awiya s army. See Ibn `Abd al-Barr, Isti'ab pp. 422 ff.
Muslim transmitted it.