Sayyidah Maymunah bint al-Harith (may Allah be pleased with her) says that she freed a slave girl in the time of the Messenger of Allah (peace and blessings be upon him). I mentioned this to the Messenger of Allah (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Had you given her to your maternal uncles, you would have received a greater reward."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7762