It has been narrated that Maimuna bint Al-Harith (May Allah be pleased with her) had set free a slave-girl without the Prophet's permission. When her turn came (the Prophet (ﷺ) used to visit his wives in turns), she made mention of that to him saying, "Did you know I have set slave-girl free?" He said, "Have you, indeed?" She replied, "Yes". He (ﷺ) then remarked, "Had you given her to your maternal uncles, you would have your reward increased".

[Al-Bukhari and Muslim].