Tradition
Mufazzal inquired from Imam Sadiq (a.s.), ‘Now most surely those who dispute obstinately concerning the hour are in great error.’ (Surah Shura (42): 18), Imam (a.s.) informed, ‘The skeptics will ask, when will his birth occur? Has anyone seen him? Where is he now? When will he reappear? Actually, this skepticism is tantamount to disbelief in Allah’s decree and destiny. These are those individuals who shall find themselves in loss and deprivation in the world and hereafter.’
Yanaabi al-Mawaddah chap 71 pg 428
