Sahih al-Bukhari 2521
Sahih al-Bukhari · Book 49: Manumission of Slaves · If one manumits a male slave owned by two persons
Narrated Ibn `Umar:
حَدَّثَنَا عَلِيُّ بْنُ عَبْدِ اللَّهِ ، حَدَّثَنَا سُفْيَانُ ، عَنْ عَمْرٍو ، عَنْ سَالِمٍ ، عَنْ أَبِيهِ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَنْ أَعْتَقَ عَبْدًا بَيْنَ اثْنَيْنِ، فَإِنْ كَانَ مُوسِرًا قُوِّمَ عَلَيْهِ ثُمَّ يُعْتَقُ " .
The Prophet (ﷺ) said, "Whoever manumits a slave owned by two masters, should manumit him completely (not partially) if he is rich after having its price evaluated."