Sahih al-Bukhari 2547
صحيح البخاري#2547SahihNarrated Abu Musa Al-Ash`ari:The Prophet (ﷺ) said, "He who has a slave-girl and teaches her good manners and improves her education and then manumits and marries her, will get a double reward; and any slave who observes Allah's right and his master's right will get a double reward
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 49:30