Riyad as-Salihin 1312
'Abdullah bin 'Amr bin Al-'As (May Allah be pleased with them) reported:
The Messenger of Allah (ﷺ) said, "Allah forgives every sin of a martyr, except his debt." [Muslim] . Another narration in Muslim is: The Messenger of Allah (ﷺ) said, "Being martyred in the Cause of Allah expiates for everything, except debt."
وعن عبد الله بن عمرو بن العاص رضي الله عنهما أن رسول الله صلى الله عليه وسلم قال‏:‏ ‏
"‏يغفر الله للشهيد كل شيء إلا الدين‏"‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏