Sahih al-Bukhari 48:1
Narrated Anas:No doubt, the Prophet (ﷺ) mortgaged his armor for barley grains. Once I took barley bread with some dissolved fat on it to the Prophet (ﷺ) 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