Sahih Muslim Book 27, Hadith Number 5592.
Chapter : The proper use of the words: Bondman, Slave-girl, Al-Maula and As-Sayyid.
Abu Huraira reported Allah’s Messenger (may peace be upon him) as saying: None of you should say: My bondman, for all of you are the bondmen of Allah, but say: My young man, and the servant should not say: My Lord, but should say: My chief.