Sayyiduna Abu al-Yasar (may Allah be pleased with him) said: I saw Sayyiduna al-Abbas bin Abd al-Muttalib (may Allah be pleased with him) standing (motionless) as if he were an idol, with tears flowing from his eyes. When I saw him, I said: "May Allah repay you with evil, you a kinsman! Do you fight your nephew alongside his enemy?" He said: "What has become of him (my nephew)? Has he been killed?" I said: "Allah is far mightier in honouring him and helping him than that." He said: "What do you want from me?" I said: "Captivity, for the Messenger of Allah (peace and blessings be upon him) has forbidden that you be killed." He said: "This is not the first of his kindnesses to his kin." So I took him captive and then brought him to the Messenger of Allah (peace and blessings be upon him).
Imam al-Tabarani (may Allah have mercy on him) said: "This hadith is narrated from Ammar bin Abi al-Yasar (may Allah have mercy on him) only with this chain; Ibrahim bin al-Mundhir is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الميم / 9123
Hadith Takhrij«أخرجه الطبراني فى «الكبير» برقم: 370»