Ashura: Day of Grief, Tragedy & Weeping
Imam Reza (peace be upon him) says:
مَن كان يوم عاشوراء يوم مُصيبته وحُزنه وبُكائه يجعل الله عزَّ وجل يوم القيامة يوم فرحه و سروره.
The one for whom the day of Ashura is a day of tragedy, grief and weeping, Allah The Mighty, The Glorious, shall make the Day of Judgment, a day of joy and happiness for him.
Bihar al‑Anwar, vol. 44, pg. 284