كتاب العتق
Read the English translation first, with the original Arabic directly underneath.
Narrated Ibn `Umar:
Allah's Messenger (ﷺ) said, "Whoever manumits his share of a slave, then it is essential for him to get that slave manumitted' completely as long as he has the money to do so. If he has not sufficient money to pay the price of the other shares (after the price of the slave is evaluated justly), the manumitted manumits the slave partially in proportion to his share. `Ubaidullah narrated as above in brief.
مَنْ أَعْتَقَ شِرْكًا لَهُ فِي مَمْلُوكٍ فَعَلَيْهِ عِتْقُهُ كُلِّهِ، إِنْ كَانَ لَهُ مَالٌ يَبْلُغُ ثَمَنَهُ، فَإِنْ لَمْ يَكُنْ لَهُ يُقَوَّمُ عَلَيْهِ قِيمَةَ عَدْلٍ، فَأُعْتِقَ مِنْهُ مَا أَعْتَقَ