Abu Dawud Book 20, Hadith Number 3722.

Chapter : Covering vessels.

Narated By Jabir ibn Abdullah : The Prophet (PBUH) said: Shut your door and make mention of Allah’s name, for the devil does not open a door which has been shut; extinguish your lamp and make mention of Allah’s name, cover up your vessel even by a piece of wood that you just put on it and make mention of Allah’s name, and tie up your water-skin mentioning Allah’s name.