A mawla of Ibn Abbas (may Allah be pleased with them both) said: I heard Maymunah (may Allah be pleased with her) say: I freed my slave girl in the time of the Messenger of Allah (peace and blessings be upon him), and I mentioned that to the Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) said: "Had you given her to your maternal relatives, it would have been greater in reward for you."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20442