Musnad Ahmad 1153:927

'Affan narrated to us, he said: Hammad ibn Salamah narrated to us, from 'Ali ibn Zayd, from al-Hasan, from 'Aishah, that the Messenger of Allah (peace and blessings of Allah be upon him) mentioned a severe hardship that would occur before the Dajjal. I said: "O Messenger of Allah, where will the Arabs be on that day?" He said: "O 'Aishah, the Arabs on that day will be few." I said: "What will suffice the believers for food on that day?" He said: "That which suffices the angels: glorifying Allah (Tasbih), magnifying Him (Takbir), praising Him (Tahmid), and declaring His oneness (Tahlil)." I said: "Then what wealth is best on that day?" He said: "A strong boy who provides water for his family, as for food, there will be no food."