when Imam Husayn (a.s.) decided to leave Madina, Umm Salama (a.s.) came to him and said, “O my dear son! Do not aggrieve me by going towards Iraq. For I have heard your Grandfather say that my son Husayn will be killed in Iraq at a place called Karbala.” Imam replied,
“O dear Grandmother! I too am aware of it and I shall be forcefully killed while there is no escape from it. By Allah! I know the day when I shall be killed and recognize my murderer besides being aware of the Mausoleum where I shall be buried. And I know all those people among my family, relatives and followers who shall die along with me. And I wish to show you the place where I shall be buried.”
Then he pointed towards Karbala and the land there at arose and he showed her the places where he would be buried, where he would lay martyred, the site of his encampment, and the place where he would halt. When Umm Salama saw this she wept bitterly and offered all decree to the Almighty. Then Imam said,
“O Grandmother! Allah Almighty desires to see me killed and that my head be severed with cruelty and injustice. Besides (Allah) desires that my family and womenfolk be expelled, and my children oppressed, bare headed, arrested and bound in chains. And they would plead and call out for help, but none would come to their aid.”
In another tradition it is stated that Umm Salama told Imam Husayn (a.s.) that, “I have with me some sand which your Grandfather had given and which lies in a bottle.” Imam replied,
“By Allah! I shall be killed even if I do not go to Iraq.”
Then he lifted a handful of earth (from the land of Karbala which had risen) and giving it to Umm Salama said, “Mix this with the sand in the bottle given to you by my Grandfather, when it turns into blood, know that I have been martyred.”
Reference : Nafasul Mahmoom – Shaikh abbas Qummi (r.a.)