Mustadrak al‑Wasail vol 10 pg. 318
Imam Redha (A.S.) said:
The one for whom the day of A'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
Imam Redha (A.S.) said
With the advent of the month of Muharram, my father Imam Kadhim (A.S.) would never be seen laughing; gloom and sadness would overcome him for (the first) ten days of the month; and when the tenth day of the month would dawn, it would be a day of tragedy, grief and weeping for him.
Amaali Saduq, pg. 111
The Holy Prophet (S.A.W.) said:
O' Fatimah! Every eye shall be weeping on the Day of Judgment except the eye which has shed tears over the tragedy of Husain (A.S.) for surely, that eye shall be laughing and shall be given the glad tidings of the bounties and comforts of Paradise.
Bihar al‑Anwar, vol. 44 pg. 193.
Imam Redha (A.S.) said (to one of his companions):
If you desire that for you be the reward equivalent to that of those martyred along with Husain (A.S.), then whenever you remember him say: ' Oh! Would that I had been with them! A great achievement would I have achieved'.
Wasaail al‑Shia'h, vol. 14, pg. 501.
Abu Haroon al‑Makfoof said:
I presented myself before Imam Sadiq (A.S.) whereupon he said to me: "Recite for me a poetry" and so I recited for him. He said "Not in this manner. Recite for me as you recite poems and elegies over the grave of Husain (A.S.)" and so I recited for him (again).
Bihar al Anwar vol 44, pg. 287.