The Book of Oaths
27/12. Chapter:
One who frees his share in a slave
Sahih Muslim
وَحَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا شُعْبَةُ، بِهَذَا الإِسْنَادِ قَالَ " مَنْ أَعْتَقَ شَقِيصًا مِنْ مَمْلُوكٍ فَهُوَ حُرٌّ مِنْ مَالِهِ " .
This hadith has been narrated on the authority of Shu'ba with the same chain of transmitters (and the words are): " He who emancipates a portion in a slave, he should (secure full) freedom for him from his property."
Reference : Sahih Muslim 1503dIn-book reference : Book 27, Hadith 79USC-MSA web (English) reference : Book 15, Hadith 4109