Musannaf Ibn Abi Shaybah 39579 — The Battle of the Trench

It is narrated from Amr bin Shurahbil that when Sayyiduna Sa'd bin Mu'adh (may Allah be pleased with him) was struck by an arrow on the day of the Trench and his blood began to flow onto the Prophet (peace and blessings be upon him), Sayyiduna Abu Bakr (may Allah be pleased with him) came and began to say: "Alas, my back is broken!" He (peace and blessings be upon him) said: "Stop, O Abu Bakr!" Then Sayyiduna Umar (may Allah be pleased with him) came and said: "Inna lillahi wa inna ilayhi raji'un (We belong to Allah and to Him we return)."