Majma al-Zawaid — Hadith 14779

Fadalah bin Abi Fadalah al-Ansari narrates: I went with my father to visit Sayyiduna Ali (may Allah be pleased with him) when he was ill. My father said to him: "Why are you staying in this place? If you were to die here, only the Bedouins of the Juhaynah tribe would see to your shrouding and burial. If you enter the city, you will be among your companions, and if something befalls you that you fear, or that we fear for you, your companions will look after you." The narrator says: Sayyiduna Abu Fadalah al-Ansari (may Allah be pleased with him) was one of the people of Badr. Sayyiduna Ali (may Allah be pleased with him) said to him: "I will not die of this illness of mine" (the narrator is unsure; perhaps the words are:) "I will not die of this ailment of mine, because the Prophet (peace and blessings be upon him) told me that I will not die until" (the narrator says: I think the words in the narration are:) "I am struck and this is dyed by that." The narrator says: Sayyiduna Abu Fadalah (may Allah be pleased with him) was martyred at the Battle of Siffin while fighting alongside Sayyiduna Ali (may Allah be pleased with him).
Al-Bazzar recorded it, and Ahmad recorded something similar; its narrators have been declared trustworthy.