Hadith 8:116
Ibn ‘Umar said that God’s Messenger forbade selling or giving away the right to inheritance from a manumitted slave. (Bukhari and Muslim.)
وَعَنِ ابْنِ عُمَرَ قَالَ: نَهَى رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَن بيع الْوَلَاء وَعَن هِبته
Original Reference: Mishkat al-Masabih 2878