Sunan an-Nasa'i, Volume 5, Book 44, Hadith 4688 (DarusSalam) ⓘ

It was narrated that Muhammad bin Jahsh said: "We were sitting with the Messenger of Allah when he raised his head toward the sky, and put his palm on his forehead, then he said: 'Subhan Allah, what a stern warning has been revealed! We fell silent and were scared. The following day I asked him: 'O Messenger of Allah, what is this stern warning that has been revealed? He said: 'By the One in Whose hand is my soul, if a man were to be killed in the cause of Allah then brought back to life, then killed, but he owed a debt, he would not enter paradise until his debt was paid off,"

أَخْبَرَنَا عَلِيُّ بْنُ حُجْرٍ، عَنْ إِسْمَاعِيلَ، قَالَ حَدَّثَنَا الْعَلاَءُ، عَنْ أَبِي كَثِيرٍ، مَوْلَى مُحَمَّدِ بْنِ جَحْشٍ عَنْ مُحَمَّدِ بْنِ جَحْشٍ، قَالَ كُنَّا جُلُوسًا عِنْدَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَرَفَعَ رَأْسَهُ إِلَى السَّمَاءِ ثُمَّ وَضَعَ رَاحَتَهُ عَلَى جَبْهَتِهِ ثُمَّ قَالَ ‏"‏ سُبْحَانَ اللَّهِ مَاذَا نُزِّلَ مِنَ التَّشْدِيدِ ‏"‏ ‏.‏ فَسَكَتْنَا وَفَزِعْنَا فَلَمَّا كَانَ مِنَ الْغَدِ سَأَلْتُهُ يَا رَسُولَ اللَّهِ مَا هَذَا التَّشْدِيدُ الَّذِي نُزِّلَ فَقَالَ ‏"‏ وَالَّذِي نَفْسِي بِيَدِهِ لَوْ أَنَّ رَجُلاً قُتِلَ فِي سَبِيلِ اللَّهِ ثُمَّ أُحْيِيَ ثُمَّ قُتِلَ ثُمَّ أُحْيِيَ ثُمَّ قُتِلَ وَعَلَيْهِ دَيْنٌ مَا دَخَلَ الْجَنَّةَ حَتَّى يُقْضَى عَنْهُ دَيْنُهُ ‏"‏ ‏.‏