Sayyiduna Abu Qatadah (may Allah be pleased with him) said: A man came to the Prophet (peace and blessings be upon him) and asked: O Messenger of Allah, if I am killed in the path of Allah, will Allah Almighty forgive my sins? He (peace and blessings be upon him) said: "If you are killed in the path of Allah while being patient, hoping for reward, advancing and not turning your back, Allah Almighty will wipe out your sins." When he (peace and blessings be upon him) had sat down, he called him and said: "What did you say?" He repeated his words, and he said: "Except debt." And the Prophet (peace and blessings be upon him) said: "Jibril (peace be upon him) informed me so."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17825