The Messenger of Allah ﷺ forbade the sale of the right of patronage and its gifting.
حدثنا سفيان حدثني عبد الله بن دينار
نهى رسول الله ﷺ عن بيع الولاء وعن هبته
Its isnad is sahih. Abdullah bin Dinar is the freed slave of Ibn Umar, a trustworthy tabii whose narration is sound, as Ahmad said. He also said that Nafi is greater than him, and that he himself is reliable, but Nafi is stronger than him. He was one of the teachers of Malik, who narrated from him frequently in Muwatta, and Sufyan Thawri and Sufyan bin Uyayna also narrated from him. Sufyan here refers to Ibn Uyayna.Malik related this hadith in Muwatta 9:2 from Abdullah bin Dinar. It was also related by the authors of the six books, as noted in al-Muntaqa 3334.