Sahih Bukhari Volume 3, Book 47, Hadith 2493

حَدَّثَنَا بِشْرُ بْنُ مُحَمَّدٍ، أَخْبَرَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا سَعِيدُ بْنُ أَبِي عَرُوبَةَ، عَنْ قَتَادَةَ، عَنِ النَّضْرِ بْنِ أَنَسٍ، عَنْ بَشِيرِ بْنِ نَهِيكٍ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ مَنْ أَعْتَقَ شَقِيصًا مِنْ مَمْلُوكِهِ فَعَلَيْهِ خَلاَصُهُ فِي مَالِهِ، فَإِنْ لَمْ يَكُنْ لَهُ مَالٌ قُوِّمَ الْمَمْلُوكُ، قِيمَةَ عَدْلٍ ثُمَّ اسْتُسْعِيَ غَيْرَ مَشْقُوقٍ عَلَيْهِ ‏"

Narrated By Abu Huraira : The Prophet said, "Whoever manumits his share of a jointly possessed slave, it is imperative for him to get that slave manumitted completely by paying the remaining price, and if he does not have sufficient money to manumit him, then the price of the slave should be estimated justly, and he is to be allowed to work and earn the amount that will manumit him (without overburdening him)".