Al-Hasan (may Allah have mercy on him) says that the Messenger of Allah (peace and blessings be upon him) said: "The bond of wala' is like the bond of lineage. It cannot be sold or given as a gift."
The Shaykh (may Allah have mercy on him) said: It has also been narrated through other routes, all of which are weak.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21435