It is narrated from Sayyiduna Sahar Abdi that the Prophet (peace be upon him) said: 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 be upon him) mentioning the tribes, I understood that what was meant were the Arabs, because non-Arabs are referred to by their cities.