It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that he said: Before the Hour, a caller will call out: "O people, the Hour has come to you!" Both the living and the dead will hear it. And Allah Almighty will descend to the lowest heaven and call out: "To whom belongs the dominion this Day? To Allah, the One, the Prevailing." [Surah Ghafir: 16] This hadith is sahih (authentic) on the condition of Imam Muslim, but the two Shaykhs (Bukhari and Muslim) did not record it.