Allah, the Most High, said:
“They ask thee about the Hour, ‘When will be its appointed time?’ Wherein art thou (concerned) with the declaration thereof? With thy Lord is the Limit fixed thereof. Thou art but a Warner for such as fear it. The Day they will see it, (it will be) as if they had tarried but a single evening, or (at most till) the following morn!” [Al-Qur’an 79:42-46]
“They ask thee about the (final) Hour – when will be its appointed time? Say: ‘The knowledge thereof is with my Lord (alone): none but He can reveal as to when it will occur. Heavy were its burden through the heavens and the earth. Only, all of a sudden will it come to you.’ They ask thee as if thou were eager in search thereof: say: ‘The knowledge thereof is with Allah (alone), but most men know not.’ ” [Al-Qur’an 7:187]
There are many ayat and ahadith concerning this subject: Allah said:
“The Hour (of Judgement) is nigh, and the moon is cleft asunder.” [Al-Qur’an 54:1]
The Prophet, upon whom be peace, said, whilst pointing with his index and middle fingers, “The time of my advent and the Hour are like these two fingers.” In another report he said, “The Hour almost came before me.” This indicates how close we are, relatively speaking, to the Hour.