Musnad Abu Ya'la al-Mawsili 4:12

Abu Bakr ibn Abi Shaybah narrated to us, Abdullah ibn Numayr narrated to us, Mujalid narrated to us, from al-Sha'bi, from Jabir, who said: I heard Umar say to Talhah ibn Ubayd Allah: "What is it that I see you disheveled and dusty since the Messenger of Allah (peace and blessings of Allah be upon him) passed away? Is it perhaps that what troubles you is the leadership of your cousin?" He said: So he said: "I seek refuge in Allah! I heard him say: 'I surely know a word that no man says when death approaches him, except that he finds his soul to be a comfort for it until it departs from his body, and it will be a light for him on the Day of Resurrection.' I did not ask the Messenger of Allah (peace and blessings of Allah be upon him) about it, and he did not inform me of it. That is what has entered into me [i.e., what is troubling me]." Umar said: "Then I know it." He said: "Praise be to Allah, so what is it?" He said: "The word which he said to his uncle." He said: "You have spoken the truth."