Sahih Bukhari Volume 004, Book 055, Hadith Number 655.

Narated By Abu Musa Al-Ash'ari : Allah's Apostle said, "If a person teaches his slave girl good manners properly, educates her properly, and then manumits and marries her, he will get a double reward. And if a man believes in Jesus and then believes in me, he will get a double reward. And if a slave fears his Lord (i.e. Allah) and obeys his masters, he too will get a double reward."

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