It is narrated from Hazrat Aisha (may Allah be pleased with her) that sometimes several months would pass in such a state that no fire would be lit in any of the houses of the Prophet (peace be upon him). Urwah (may Allah have mercy on him) says: I asked, "Aunt! Then how did you manage?" She replied: "On two black things, that is, dates and water."
Hadith Referenceمسند احمد / مسند النساء / 24420
Hadith Gradingحکم دارالسلام:حديث صحيح، خ: 2567، م: 2972، بزيادة يزيد بن رومان بين أبى حازم وعروة