كتاب الأيمان
27  
The Book of Oaths
(12)
Chapter: One who frees his share in a slave
(12)
باب مَنْ أَعْتَقَ شِرْكًا لَهُ فِي عَبْدٍ ‏‏
Sahih Muslim 1503 e

Abu Huraira reported Allah's Apostle (ﷺ) as saying:

He who emancipates his portion in a slave, full emancipation may be secured for him out of his property (if he has money) if he has enough property to meet (the required expenses), but if he has not enough property, the slave should be put to extra labour (in order to earn money for buying his freedom), but he should not be overburdened.
وَحَدَّثَنِي عَمْرٌو النَّاقِدُ، حَدَّثَنَا إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، عَنِ ابْنِ أَبِي عَرُوبَةَ، عَنْ قَتَادَةَ، عَنِ النَّضْرِ بْنِ أَنَسٍ، عَنْ بَشِيرِ بْنِ نَهِيكٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ مَنْ أَعْتَقَ شَقِيصًا لَهُ فِي عَبْدٍ فَخَلاَصُهُ فِي مَالِهِ إِنْ كَانَ لَهُ مَالٌ فَإِنْ لَمْ يَكُنْ لَهُ مَالٌ اسْتُسْعِيَ الْعَبْدُ غَيْرَ مَشْقُوقٍ عَلَيْهِ ‏"‏ ‏.‏
Reference : Sahih Muslim 1503e
In-book reference : Book 27, Hadith 80
USC-MSA web (English) reference : Book 15, Hadith 4110
  (deprecated numbering scheme)