Musnad Ahmad 30:1338

Yunus and Surayj narrated to us, they said: Fulayh narrated to us, from Sa’id ibn ‘Ubayd ibn al-Sabbaq, from Abu Hurayrah, from the Messenger of Allah, may Allah bless him and grant him peace, that he said: "Lands and cities will be conquered, and men will say to their brothers: 'Come to the countryside,' while the city is better for them if they only knew. No one will endure its hardship and its severity except that I will be a witness or an intercessor for him on the Day of Resurrection."