Bulugh al-Maram, Book 15, Hadith 1472 (English)

'A’ishah (RAA) narrated that The Messenger of Allah said: “Wala’ is (legally) for the manumitter.” Agreed upon. It is part of a long Hadith (refer to hadith no. 811).

وَعَنْ عَائِشَةَ رَضِيَ اَللَّهُ عَنْهَا; أَنَّ رَسُولَ اَللَّهِ ‏- صلى الله عليه وسلم ‏-قَالَ: { "إِنَّمَا اَلْوَلَاءُ لِمَنْ أَعْتَقَ" } مُتَّفَقٌ عَلَيْهِ فِي حَدِيث ٍ 1‏.‏ ‏1 ‏- تقدم برقم ( 790 )‏.‏

sunnah.com

also referenced under: Book 15, Hadith 1428 (In-Book)