Sahih Muslim:
Book 27, Number 5594: Abu Huraira reported Allah's Messenger (may peace be upon him) so many ahadith and one of them is this that Allah's Messenaer (may peace be upon him) said: None of you should say: Supply drink to your lord, feed your lord, hell) your lord in performing ablution, and none of you should say: My Lord. He should say: My chief, my patron; and none of you should say: My bondman, my slave-girl, but simply say: My boy, my girl, my servant.