It has been narrated on the authority of Abu Qatada that the Messenger of Allah (ﷺ) stood up among them (his Companions) to deliver his sermon in which he told them that Jihad in the way of Allah and belief in Allah (with all His Attributes) are the most meritorious of acts. A man stood up and said
Messenger of Allah, do you think that if I am killed in the way of Allah, my sins will be blotted out from me? The Messenger of Allah (ﷺ) said: Yes, in case you are killed in the way of Allah and you were patient and sincere and you always fought facing the enemy, never turming your back upon him. Then he added: What have you said (now)? (Wishing to have further assurance from him for his satisfaction), he asked (again): Do you think if I am killed in the way of Allah, all my sins will be obliterated from me? The Messenger of Allah (ﷺ) said: Yes, it you were patient and sincere and always fought facing the enemy and never turning your back upon him, (all your lapses would be forgiven) except debt. Gabriel has told me this.
The tradition has been narrated through a different chain of transmitters on the authority of Abu Qatada who said
A man came to the Messenger of Allah (ﷺ) while he was on the pulpit and said: Do you think if I am killed in the way of Allah... (except this difference in its beginning, the rest of the tradition is the same as the previous one).
Another version of the tradition differently transmitted begins with the words
" A man came to the Messenger of Allah (ﷺ) and he was sitting on the pulpit.... He said: What do you find if I strike with the sword?" (The rest of the tradition is the same as the previous one.)
It has been reported on the authority of 'Amr b. al-'As that the Messenger of Allah (ﷺ) said
All the sins of a Shahid (martyr) are forgiven except debt.
It has been reported on the authority of Amr b. al-'As through a different chain of transmitters that the Messenger of Allah (ﷺ) said
Death in the way of Allah blots out everything except debt.