Mishkat al-Masabih 14 Emancipation كتاب العتق 20

وَعَنْ عَمْرِو بْنِ شُعَيْبٍ عَنْ أَبِيهِ عَنْ جَدِّهِ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: ” مَنْ كَاتَبَ عَبْدَهُ عَلَى مِائَةِ أُوقِيَّةٍ فَأَدَّاهَا إِلَّا عَشْرَ أَوَاقٍ أَوْ قَالَ: عَشْرَةَ دَنَانِيرَ ثُمَّ عَجَزَ فَهُوَ رَقِيقٌ ” . رَوَاهُ التِّرْمِذِيّ وَأَبُو دَاوُد وَابْن مَاجَه

‘Amr b. Shu’aib, on his father’s authority, told that his grandfather reported God’s Messenger as saying, “If anyone has agreed to let his slave buy his freedom for a hundred uqiyas and he pays them all but ten (or he said, ten dinars), and he is then unable to complete the amount, he remains a slave.” Tirmidhi, Abu Dawud and Ibn Majah transmitted it.