Sahih Bukhari
Drinks
Volume: 007 / Book Number: 069 / Hadith Number: 528
Narrated Jabir:
Allah's Apostle said, "Extinguish the lamps when you go to bed; close your doors; tie the mouths of your water skins, and cover the food and drinks." I think he added, ". . . even with a stick you place across the container."