Abdullah bin Sa'id al-Ashaj عبد الله بن سعيد بن حصين الكندي - الأشج · The Book on Marriage

"Three will receive their reward twice: A slave who fulfills the rights of Allah and the rights of his owners, then he will be given his reward twice. And a man who has a beautiful slave girl, so he teaches her good manners, then he frees her, then he married her seeking the Face of Allah by that; then he will be given his reward twice. And a man who believed in an earlier Book, then another Book came to…