Sahih Muslim 4325
The Book of Oaths
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قُلْتُ لِمَالِكٍ حَدَّثَكَ نَافِعٌ، عَنِ ابْنِ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ أَعْتَقَ شِرْكًا لَهُ فِي عَبْدٍ فَكَانَ لَهُ مَالٌ يَبْلُغُ ثَمَنَ الْعَبْدِ قُوِّمَ عَلَيْهِ قِيمَةَ الْعَدْلِ فَأَعْطَى شُرَكَاءَهُ حِصَصَهُمْ وَعَتَقَ عَلَيْهِ الْعَبْدُ وَإِلاَّ فَقَدْ عَتَقَ مِنْهُ مَا عَتَقَ " .
Ibn 'Umar reported Allah's Messenger (ﷺ) as saying:He who gives up his share in a slave, and has enough money to pay the full price of the slave, then full emancipation devolves upon him; but if he has not the money, then he emancipated what he emancipated
Text from the public-domain hadith-api dataset. Numbering follows that dataset and can differ by a few from some printed editions — check the wording, not only the number.