Sahih Bukhari

Narrated Kuraib:the freed slave of Ibn `Abbas, that Maimuna bint Al-Harith told him that she manumitted a slave-girl without taking the permission of the Prophet. On the day when it was her turn to be with the Prophet, she said, ""Do you know, O Allah's Messenger (ﷺ), that I have manumitted my slave-girl?"" He said, ""Have you really?"" She replied in the affirmative. He said, ""You would have got more reward if you had given her (i.e. the slave-girl) to one of your maternal uncles