" The Prophet (may Allah's peace and blessings be upon him) prohibited the selling and gifting of Walā' (the right of a master to inherit from his freed slave by virtue of the bond of loyalty between them). [Al-Bukhari]"

"عن عبد الله بن عمر- رضي الله عنهما- مرفوعاً: «أن النبي -صلى الله عليه وسلم- نهى عن بيع الوَلاءِ وعن هِبَتِهِ». [صحيح.] - [متفق عليه.]"