It is mentioned in the book Majmaul Bahrayn that: “Revenger is one who under no circumstance rests till he does not avenge the blood shed from his side.”
We read in Ziarat Aashura:
“I beg Allah, Who honored you above others, to be generous towards me on account of you, and give me the opportunity to be with the victorious Imam, the descendant of Muhammad (s.a.w.s.) at the time of the final and decisive war to take revenge for you.”
And in Bihar quoting from Ghaibat Nomani from Abu Ja’far Baqir (a.s.) under the description of the qualities of Imam Qaim (a.t.f.s.) he said:
“His mission is nothing but the complete extermination (of those who will oppose him). He will not leave anyone from the enemies of truth.”
And Ayyashi has mentioned in the exegesis of the verse:
“And whoever is slain unjustly, We have indeed given to his heir authority, so let him not exceed the just limits in slaying; surely he is aided.”
The report of Salaam bin al-Mustanir from Imam Baqir (a.s.) that he said:
“It was Husain bin Ali (a.s.) that was martyred unjustly and we are his successors. When the Qaim from us rises he will set out to revenge the blood of Husain (a.s.). Then he will unleash such killings that it will be alleged that he is doing Israaf (excess) in killing.”
The Imam also said:
“The one killed is Husain (a.s.) and his Wali is Qaim (a.s.). And the Israaf in that killing is: He would kill other than his killer, (that is Mansoor) because he will not leave the world till by the medium of a man from the progeny of the Messenger of Allah (s.a.w.s.) he gets help and victory such that he would fill the earth with justice and equity just as it would have been fraught with injustice and oppression.”
And in another traditional report in Kafi from Imam Ja’far Sadiq (a.s.) with reference to the same verse it is mentioned:
“It was revealed about Husain (a.s.) if the people of the earth are killed due to him it is not Israaf (excess).”
In the book Ilalush Sharai it is narrated from Imam Baqir (a.s.) that he said:
“When my grandfather, Husain (a.s.) was martyred the angels rose up their lamentations of protest in the court of Allah, the Mighty and the Sublime, and they said: “O God, owner of discretion! Will you ignore the one who has killed Your chosen one, son of Your chosen one and the best of the creation?”
The Almighty Allah revealed to them: “O My angels, rest assured. By My Mighty and Glory, I will indeed take revenge from them — even if it be after sometime.” After that Allah, the Mighty and Sublime, removed the veil from the faces of the Imams from the progeny of Husain (a.s.). The angels became glad and noticed that one of them was standing up in prayers. Allah said: “I will take revenge from them from this Qaim (the standing one).”
And in Kafi it is narrated from His Eminence, Abi Abdullah Sadiq (a.s.) that he said:
“When Husain (a.s.) was martyred, the heavens and the earth and all that are in it lamented and said: “Lord, permit us to destroy all the creatures and to renew the earth again as they have considered Your sanctity lawful (to defile) and have slain Your chosen one.” So the Almighty Allah revealed to them, “O angels, O My heavens and O My earth! Rest assured!” Then He removed a curtain behind which were visible, Muhammad and his twelve successors. He held the hand of the Qaim from among them and said: O My angels and O My heavens and O My earth, I will help them. He repeated it thrice.”
And in Ghayat al-Maraam the Sayyid Hashim Bahrani has quoted a tradition from the Ahle Sunnat channels in the narration of Me ‘raaj (ascension) as follows:
“The Almighty Allah said: O Muhammad! would you like to see them? I said: Yes! The Lord said: Turn towards the right of the Arsh. When I turned in that direction, I immediately saw Ali, Fatima, Hasan, Husain, Ali bin al-Husain, Muhammad bin Ali, Ja’far bin Muhammad, Moosa bin Ja’far, Ali bin Moosa, Muhammad bin Ah, Ali bin Muhammad, Hasan bin Ah and Mahdi (a.s.) surrounded by effulgence, reciting the prayers in standing position. And he that is Mahdi (a.s.) was among them like a brilliant star. The Almighty Allah said: These are the Divine Proofs and he is the revenger of your progeny. By My honor, he is the necessary proof for My friends and the revenger from My enemies.”
And in Biharul Anwar the qualities of Imam Mahdi (a.s.) are described by Imam Sadiq (a.s.) in the following tradition:
“There will be some men whose hearts will be as strong as iron and who will not have an iota of doubt and regarding their faith in Allah they shall be as solid as rocks. They shall be so valiant that if they were to attack mountains, they could move them from their place, and to whichever area they turn they shall destroy it and for seeking blessings and to create courage in the hearts they will keep kissing the saddle of Imam Qaim (a.s.). They shall be right up to the expectations of the Imam.
They shall be men that do not sleep at night. They shall be busy all night in prayers. The sound of them reciting the Quran will seem like humming of the bees. They shall spend the night standing and in the morning mount their horses. In the night they will be like monks and ascetics and in the day they shall be like ferocious lions. They shall be more obedient to their Imam than a slave girl is to her master. Their heart (from the aspect of faith) will be like lanterns in which the lamp is lighted. They shall be fearful of Allah. They shall invite towards martyrdom. They shall be eager to be killed in the way of God. Their slogan shall be: Yaa Tharatal Husain! That is: “Revenge of the blood of Husain!” When they march, their awe shall precede them for a distance of one month’s travel (far away). It is through them that Allah will help the true Imam.”
And it is further narrated from Imam Sadiq (a.s.) that he said:
“When the Qaim (a.s.) rises up, he will slay the grandsons (descendants) of the killers of Husain (a.s.).”
Source: https://thepromisedmahdi.com