question #3 Sahih al-Bukhari 5083, Book 67, Hadith 21 : What is the significance of fulfilling duties to both one’s master and Allah in the context of earning rewards?

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.”