one day the Holy Prophet Muhammad (S) was seated and Imam Ali (a.s.), Hazrat Fatima (a.s.), Imam Hasan (a.s.), and Imam Husayn (a.s.) were sitting around him. The Prophet addressed them and said,
“What will be your state when all of you will be killed and your graves will lie scattered”?
Imam Husayn (a.s.) said,
“Will we die a natural death or will we be martyred”?
The Prophet replied,
“O my dear son! You will be killed with oppression and cruelty, and your brother (Hasan) too will be killed with tyranny and cruelty, and your offspring will be scattered over the land.”
Husayn asked, “Who will kill us, O Prophet of Allah”?
He replied, “The worst among men”,
then Imam Husayn inquired, “Then will anyone come to visit us (our graves) after our death”?
The Prophet answered,
“Yes my dear son! A group of people from among my community will come to visit your graves seeking my pleasure. Then on the day of Qiyamah, near the station of accounting, I will go to them and catching hold of their hands will save them from it’s terrors and sorrows.”
Reference : Nafasul Mahmoom – Shaikh abbas Qummi (r.a.)