Sunan an-Nasa'i 4699
It was narrated that Ibn 'Umar said:
"The Messenger of Allah said: 'Whoever sets free his share of a slave, and he has sufficient wealth to set him free completely by paying the price of the slave, then he should set him free with his own wealth."'
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَزِيدُ، - وَهُوَ ابْنُ زُرَيْعٍ - قَالَ حَدَّثَنَا أَيُّوبُ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ مَنْ أَعْتَقَ شِرْكًا لَهُ فِي مَمْلُوكٍ وَكَانَ لَهُ مِنَ الْمَالِ مَا يَبْلُغُ ثَمَنَهُ بِقِيمَةِ الْعَبْدِ فَهُوَ عَتِيقٌ مِنْ مَالِهِ ‏"‏ ‏.‏