(14) باب فَضْلِ مَنْ أَدَّبَ جَارِيَتَهُ وَعَلَّمَهَا
Narrated Abu Musa:
Allah's Messenger (ﷺ) said, "He who has a slave-girl and educates and treats her nicely and then manumits and marries her, will get a double reward."
Reference: Sahih al-Bukhari 2544
In-book reference: Book 49, Hadith 28
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 46, Hadith 720