Musnad Ahmad 30:956

Muhammad ibn Bakr narrated to us, Abd al-Hamid ibn Ja'far al-Ansari narrated to us, Iyad ibn Abdullah ibn Abi Sarh informed me, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) stood to address the people, and he mentioned faith in Allah and Jihad in the way of Allah as being among the best of deeds before Allah. A man stood up and said: "O Messenger of Allah, do you see that if I am killed in the way of Allah while I am patient, seeking reward, advancing and not retreating, will Allah expiate my sins for me?" He said: "Yes." He said: "What did you say?" So he repeated the statement to him as he had said it. He said: "Yes." He said: "What did you say?" He repeated the statement to him again. He said: "O Messenger of Allah, do you see that if I am killed in the way of Allah while I am patient, seeking reward, advancing and not retreating, will Allah expiate my sins for me?" He said: "Yes, except for debt, for Jibril whispered that to me."