Sunan Abi Dawud 1690
سنن أبي داود#1690SahihMaimunah, wife of the Probhet (ﷺ) said :I had a slave girl and I set her free. When the Prophet (ﷺ) entered upon me, I informed him (of this). He said : May Allah give reward for it; if you had given her to your maternal uncles, it would have increased your reward
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Muhyi Al-Din Abdul HamidSahih
Zubair Ali ZaiSahih
In-book reference: 9:135