Musnad Ahmad 32:1226

Rawh and ‘Abd al-Samad narrated to us, they said: Hisham ibn Abi ‘Abd Allah narrated to us, from Qatadah, from Anas ibn Malik, that he walked to the Messenger of Allah (may Allah bless him and grant him peace) with barley bread and rancid fat. And he had indeed pawned his armor to a Jew, and took barley for his family. And I indeed heard him one day saying—‘Abd al-Samad said: He said that repeatedly—: "The family of Muhammad did not have a sa’ of wheat, nor a sa’ of grain, in the evening." And he had nine wives at that time.