(10) باب بَيْعِ الْوَلاَءِ وَهِبَتِهِ
Narrated Ibn `Umar:
Allah's Messenger (ﷺ) forbade the selling or donating the Wala' of a freed slave.
Reference: Sahih al-Bukhari 2535
In-book reference: Book 49, Hadith 20
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 46, Hadith 712