By Allah, my nephew, we would sight the new moon, then another new moon, then another, three new moons in two months, without a fire being lit in the houses of the Messenger of Allah ﷺ.I asked, "Auntie, what kept you alive then?"She replied, "The two black things, dates and water. However, the Messenger of Allah ﷺ had neighbors from the Ansar who owned milk-giving animals, and they used to send some of their milk to the Messenger of Allah ﷺ, and he would give it to us to drink."
والله يابن أختي إن كنا لننظر إلى الهلال ثم الهلال ثم الهلال ثلاثة أهلة في شهرين، وما أوقد في أبيات رسول الله ﷺ نار، قال: قلت: يا خالة، فما كان يعيشكم؟ قالت: الأسودان: التمر والماء إلا أنه قد كان لرسول الله ﷺ جيران من الأنصار، وكانت لهم منائح، فكانوا يرسلون إلى رسول الله ﷺ من ألبانها، فيسقيناه.
Bukhari related it in the chapter on Softening of Hearts (6459), and Muslim in Asceticism and Softening of Hearts (29:2972), both through Abdul-Aziz bin Abu Hazim, from Yazid bin Ruman, from Urwa, from Ayesha, and I have related it accordingly, the wording being Muslim's.