سنن النسائي

It was narrated from 'Abdullah bin Abi Qatadah that his father said: "A man came to the Prophet (ﷺ) when he was on the Minbar and said: 'O Messenger of Allah, do you think that if I wield this sword of mine in the cause of Allah, with patience and seeking reward, facing the enemy, and not running away, will Allah forgive my sins?' He said: 'Yes.' When he turned away, he called him back and said: 'Jibril says: unless you are in debt.'"