Islam Guidance

Shaikh Mufeed has narrated through his chain of transmitters that Imam Sadiq (A.S) said, that when Imam Hussein (A.S) left Medina, a group of Angels, having distinct marks, met him on the way. They carried swords in their hands and had mounted the horses of Paradise. They came to Imam (A.S), saluted him and said: "O Allah's Proof (Hujjah) upon the creatures after your Grandfather, Father and Brother! Allah the Glorious had rendered help to your Grandfather through our medium in many of his battles, and has now sent us to assist you." Imam (A.S) replied: "The Promised Land is called Karbala, thus you may come to me there."
They said: "O Proof of Allah! You may command whatever you desire and we will comply with it and obey you. If you fear the enemies we shall defend you against them."
Imam (A.S) replied:
"They have no way upon me and they will not be able to hurt me until I reach my (destined) mausoleum."

Derived from: Nafasul Mahmoom   
By: Sheikh Abbas Qummi

They were the faithful friends, helpers and companions of Imam Hussein (A.S). Some were old like Habib ibn Madhahir; others like Wahab al Kalbi were young. Some were noblemen like Zuhayr ibn Qayn, others like Jawn bin Huwai were slaves. Some like Salim and Amir came from towns like Kufa and Basra; others had lived in the desert. There were men like Ammar and Muslim ibn Awsaja, who had been with the Prophet (P.B.U.H&H.P) and Nafi and Jundab, who were friends of Imam Ali (A.S). They were all killed fighting bravely against the army of Umar ibn Saad, defending Islam on the day of Ashura and the Imam (A.S) wept for each of them.

Ref: Shia books for children