The Book of Drinks (Kitab Al-Ashriba)

Muslim :: Book 23 : Hadith 4987

Abu Humaid Sa'idi reported: I came to Allah's Messenger (may peace be upon him) with a cup of milk from Naqi' which had no cover over it, whereupon he said: Why did you not cover it? - even if you had covered it only with a stick. Abu Humaid said that he had been ordered that waterskins be tied during the night, and the doors be closed during the night.