Musnad Ahmad 30:2126

Khalaf narrated to us, he said: Abu Ma’shar narrated to us, from Sa’id, from Abu Hurairah, who said: "A crescent would pass, then another crescent, for the family of the Prophet, may Allah bless him and grant him peace, and no fire would be kindled in any of their houses, neither for bread nor for cooked food." They said: "What did they live on, O Abu Hurairah?" He said: "The two black things: dates and water. And they had neighbors from the Ansar—may Allah reward them with good—who had milch camels, and they would send them some milk."