It is narrated from Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "The slave who worships his Lord properly, and also fulfills the rights of obedience and goodwill that his master has upon him with responsibility, for him there is a double reward."
Hadith Referenceالادب المفرد / كتاب / 204
Hadith Gradingالألبانی:صحيح
Hadith Takhrij«صحيح : أخرجه البخاري ، كتاب العتق ، باب كراهية التطاول على الرقيق : 2551»