Anas (Ra) narrates that Rasúlullãh (saw) said: The Hour of the Day of Resurrection will not come until there will be no one left in the world who says Allãh, Allãh. And in another narration: The Hour of the Day of Resurrection will not be established so long as there is someone saying, Allãh, Allãh.

(Muslim)

Note: This means that the Day of Resurrection will occur when the world becomes devoid of Allãh's remembrance. This Hadíth also explains that the Day of Resurrection will not be established so long there is a single man saying: O people! Fear Allãh and worship Him.

(Mirqãt)