(a) Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) narrates from the Prophet (peace and blessings be upon him) that he (peace and blessings be upon him) said: "Being martyred in the path of Allah wipes out all sins, except that debt remains." (b) Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates from the Prophet (peace and blessings be upon him): "The soul of the believer remains suspended because of his debt until it is paid off on his behalf."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 17826