كتاب العتق
20  
The Book of Emancipating Slaves
(2)
Chapter: A slave working to pay off the other half
(2)
باب ذِكْرِ سِعَايَةِ الْعَبْدِ ‏‏
Sahih Muslim 1503 b

This hadith has been narrated on the authority of Sa'id b. Abu 'Aruba with the same chain of transmitters but with the addition:

" If he (one of the joint owners emancipating the slave) has not (enough) money (to secure freedom for the other half) a fair price for the slave should be fixed, and he will be required to work to pay for his freedom, but must not be over-burdened.
وَحَدَّثَنَاهُ عَلِيُّ بْنُ خَشْرَمٍ، أَخْبَرَنَا عِيسَى، - يَعْنِي ابْنَ يُونُسَ - عَنْ سَعِيدِ بْنِ، أَبِي عَرُوبَةَ بِهَذَا الإِسْنَادِ وَزَادَ ‏ "‏ إِنْ لَمْ يَكُنْ لَهُ مَالٌ قُوِّمَ عَلَيْهِ الْعَبْدُ قِيمَةَ عَدْلٍ ثُمَّ يُسْتَسْعَى فِي نَصِيبِ الَّذِي لَمْ يُعْتِقْ غَيْرَ مَشْقُوقٍ عَلَيْهِ ‏"‏ ‏.‏
Reference : Sahih Muslim 1503b
In-book reference : Book 20, Hadith 5
USC-MSA web (English) reference : Book 9, Hadith 3582
  (deprecated numbering scheme)