It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said on the Day of Badr: "Whoever of you meets Abbas (my uncle) should not kill him, for he has been forced to come out." Hearing this, Sayyiduna Abu Hudhayfah bin Utbah (may Allah be pleased with him) said: Are we to kill our fathers, our brothers and our kinsmen and leave Abbas?! By Allah, if I meet him, I will make him food for my sword. This reached the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said to Umar bin al-Khattab (may Allah be pleased with him): "O Abu Hafs!" Sayyiduna Umar (may Allah be pleased with him) said: That was the first day on which he (peace and blessings be upon him) called me by my kunyah Abu Hafs. He (peace and blessings be upon him) said: "Is the face of the uncle of the Messenger of Allah to be struck with the sword?" Sayyiduna Umar (may Allah be pleased with him) said: (O Messenger of Allah!) Let me strike off his neck, for he has become a hypocrite. Sayyiduna Abu Hudhayfah (may Allah be pleased with him) used to say (later, in remorse): Because of that sentence which I said that day, I never consider myself safe, and I remain constantly afraid until Allah Almighty expiates it for me through martyrdom. So he was martyred on the day of the Battle of al-Yamamah. This hadith is sahih (authentic) on the condition of Muslim, but the two Shaykhs (Bukhari and Muslim) did not record it.