It is narrated from Hazrat Sahar Abdi that I heard the Prophet (peace and blessings be upon him) say: The Hour will not be established until some tribes are swallowed up by the earth, and people will begin to ask, "How many people are left from such-and-such tribe?" When I heard the Prophet (peace and blessings be upon him) mention tribes, I understood that this referred to the Arabs, because non-Arabs are attributed to their cities.