Sahih Bukhari Volume 3, Book 45, Hadith Number 685.

Narated By Anas : No doubt, the Prophet mortgaged his armor for barley grams. Once I took barley bread with some dissolved fat on it to the Prophet and I heard him saying, “The household of Muhammad did not possess except a Sa (of food grain, barley, etc.) for both the morning and the evening meals although they were nine houses.”