Imam al-Sadiq (AS) narrated, ‘Jesus son of Mary (AS) asked Gabriel (AS), ‘When will the Hour come upon which Gabriel started to tremble so severely that he fainted from it. When he came to his senses, he said, ‘
O Spirit of Allah, the questioned one does not know that any more than the questioner does. To Him belongs all that is in the heavens and the earth, and it [the Hour] will take you all by surprise.