Sahih Muslim | Book 30 | Hadith Number 5661
Narrated by Jabir
Jabir reported that a person came to Allah's Apostle (may peace be upon him) and asked for food. And he gave him half a wasq of barley, and the person and his wife and their guests kept on making use of it (as a food) until he weighed it (in order to find out the actual quantity, and it was no more). He came to Allah's Apostle (may peace be upon him) (and informed him about it). He said: Had you not weighed it, you would be eating out of it and it would have remained intact for you.