Imam al-Sajjad (as): Imam Zayn al-Abidin (AS) said in one of his exhortations, ‘Know O son of Adam that beyond this [life] is something greater, more horrendous and more painful for the hearts [the Day of Resurrection]. That is a Day for which the people will be collected, and that is a Day [which will be] witnessed, wherein Allah will gather people from the first to the last.’ al-Kāfī