Sahih Bukhari Volume 8, Book 76, Hadith Number 466.

Narated By ‘Aisha : That she said to Urwa, “O, the son of my sister! We used to see three crescents in two months, and no fire used to be made in the houses of Allah’s Apostle (i.e. nothing used to be cooked).” ‘Urwa said, “What used to sustain you?” ‘Aisha said, “The two black things i.e. dates and water, except that Allah’s Apostle had neighbors from the Ansar who had some milch she-camels, and they used to give the Prophet some milk from their house, and he used to make us drink it.”