'A'ishah (RAA) narrated that The Messenger of Allah (ﷺ) said:
"Wala' is (legally) for the manumitter." Agreed upon. It is part of a long Hadith (refer to hadith no. 811). (FR)
English reference (FR): Book 15, Hadith 1472 (FR)
Arabic reference (FR): Book 15, Hadith 1428 (FR)