Allah’s Messenger (ﷺ) said “Three persons will have a double reward: 1. A Person from the people of the scriptures who believed in his prophet (Jesus or Moses) and then believed in the Prophet (ﷺ) Muhammad (i .e. has embraced Islam). 2. A slave who discharges his duties to Allah and his master. 3. A master of a woman-slave who teaches her good manners and educates her in the best possible way (the religion) and manumits her and then marries her.”
The Prophet (ﷺ) said, “Three persons will get their reward twice. (One is) a person who has a slave girl and he educates her properly and teaches her good manners properly (without violence) and then manumits and marries her. Such a person will get a double reward. (Another is) a believer from the people of the scriptures who has been a true believer and then he believes in the Prophet (ﷺ) (Muhammad). Such a person will get a double reward. (The third is) a slave who observes Allah’s Rights and Obligations and is sincere to his master.”
Allah’s Messenger (ﷺ) said, any man who has a slave girl whom he educates properly, teaches good manners, manumits and marries her, will get a double reward And if any man of the people of the Scriptures believes in his own prophet and then believes in me too, he will (also) get a double reward And any slave who fulfills his duty to his master and to his Lord, will (also) get a double reward.”