It is narrated about Sayyida Maymunah bint Harith (may Allah be pleased with her). In the blessed era of the Prophet Muhammad (peace be upon him), she freed her slave girl. She mentioned this to the Prophet Muhammad (peace be upon him), so the Prophet Muhammad (peace be upon him) said: If you had given her to your maternal uncles, it would have been more rewarding for you.
Hadith Referenceصحیح ابن حبان / كتاب الزكاة / 3343
Hadith Gradingفضيلة الشيخ الإمام محمد ناصر الدين الألبانيصحيح: م.فضيلة الشيخ العلّامة شُعيب الأرناؤوطإسناده صحيح على شرط مسلم