Qur'an 16:77 The business of the Final Hour shall be accomplished in the twinkling of an eye, or in a shorter time.

Imam Hasan and Husain

1. After the assassination of their father, ʿAlī, Ḥasan and Ḥusayn acquiesced to the rule of the first Umayyad caliph, Muʿāwiya.

acquiesce

to accept sth without arguing, even if you do not really agree with it

She explained her plan and reluctantly he acquiesced.

2. Ḥusayn, however, refused to recognize the legitimacy of Muʿāwiya’s son and successor, Yazīd  (April 680).

3. Ḥusayn was invited by the townsmen of Kūfah to come there and raise the standard of revolt against the Umayyads.

4. The governor of Iraq sent 4,000 men to arrest Ḥusayn and his small band. They trapped Ḥusayn near the banks of the Euphrates River (October 680). 

5. When Ḥusayn refused to surrender, he and his escort were slain.

6. Revenge for Ḥusayn’s death was turned into a rallying cry that helped undermine the Umayyad caliphate.

rallying cry

a phrase or an idea that is used to encourage people to support sb/sth