Imam Muhammad al Baqir (a.s.) said that, one day the Holy Prophet Muhammad (S) was in the house of the mother of the faithful Umm Salama (a.s.), his wife, and told her not to allow anyone to visit him. Imam Husayn (a.s.), who was a child at that time, entered therein and rushed to the Prophet (S). Umm Salama (a.s.) followed him and saw Imam Husayn (a.s.) seated on the chest of the Prophet (S) and the Prophet (S) was weeping. In his hand there was something which he was turning upside down. Then he said,
“O Umm Salama! Jibra’eel has come to me and reported that my Husayn will be martyred and this earth is of his place of martyrdom. Preserve this with you, and the day this earth turns into blood, know then that Husayn has been martyred.”
Umm Salama said, “O Prophet of Allah! Pray to Allah to relieve Husayn from this calamity.” The Prophet replied,
“Yes I prayed to Allah for it, but Allah revealed to me that due to his martyrdom, a status will be bestowed on him, which will be unapproachable by anyone else. And he will be having such followers (Shi’ah) who will intercede (on the day of Qiyamah) and their intercession (Shafa’ah) will be accepted. And that Mahdi (a.t.f.s.) will be from his progeny. Hence how good for them who will befriend Husayn and will be among his followers (Shi’ah). For verily on the day of Qiyamah they will be successful.”
Reference : Nafasul Mahmoom – Shaikh abbas Qummi (r.a.)