It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him), he says: On the day of the conquest of Makkah, I was standing beneath the mount of the Messenger of Allah (peace and blessings be upon him). The Prophet (peace and blessings be upon him) spoke very beautiful and eloquent words. Among them was this:“Whoever from among the People of the Book becomes a Muslim, he will have a double reward, and then whatever right is ours will also be his, and whatever responsibility is upon us will also be upon him. And whoever from among the polytheists becomes a Muslim, he will receive his reward, and then whatever right is ours will also be his, and whatever responsibility is upon us will also be upon him.”

It is narrated from Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: "Whoever teaches his slave-girl and teaches her well, and gives her good moral training and trains her well, then sets her free and marries her, he will receive a double reward. (Similarly, there are two rewards) for the slave who fulfills the right of Allah Almighty and also the right of his master, and for the person from the People of the Book who first believed in the Shari'ah brought by Jesus (peace be upon him) and then believed in the Shari'ah brought by Muhammad (peace and blessings be upon him), for him also there are two rewards."