From Sahih Bukhari (Hadith 2069):
Narrated Qatada:Anas went to the Prophet (ﷺ) with barley bread having some dissolved fat on it. The Prophet (ﷺ) had mortgaged his armor to a Jew in Medina and took from him some barley for his family. Anas heard him saying, "The household of Muhammad did not possess even a single Sa of wheat or food grains for the evening meal, although he has nine wives to look after." (See Hadith No)
Reference: Bukhari 2069