It is narrated from Sayyiduna Salamah bin al-Akwa' (may Allah be pleased with him) that his uncle, Sayyiduna Amir bin al-Akwa' (may Allah be pleased with him), was wounded on the day of Khaybar and he had killed a man, so the Messenger of Allah (peace and blessings be upon him) said: "He has a double reward."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated it from Muhammad bin Bishr except Abu Ahmad."
Hadith Referenceالمعجم الأوسط / باب الألف / 2151
Hadith Takhrij«أخرجه الطبراني فى «الكبير» برقم: 6274، والطبراني فى «الأوسط» برقم: 1628»