Those who killed Al-Ḥusayn (may his glory be exalted) are those who claimed to love him and support him, and about whom our Master Al-Ḥusayn (may his glory be exalted) said, concerning the people of Kūfah:
"Yes, by Allah, treachery is ancient among you, its roots are intertwined, and its branches are strengthened. So, you were the foulest fruit, a sorrow for the observer, and a morsel for the usurper."1
Yes, by Allah, ancient treachery! hey are the Children of Israel, the betrayers of the prophets, about whom he said in another tradition:
From Al-Mufaḍḍal ibn ‘Umar (from him is peace), our Master Al-Ṣādiq (may his glory be exalted) said: "Allah mentioned the killers of Al-Ḥusayn in the latter times, who visit his grave and seek healing with his soil. They are the killers of the prophets in every era." Muḥammad ibn Sinān (peace be upon him) said: I presented this tradition to our Master Al-Riḍā (may his glory be exalted). He said: "Al-Mufaḍḍal spoke the truth. He is the door of Allah on His earth and the lamp for the believers in the darkness, and he is the son after the father." I said: "O my master, after which father?" He said: "After Abī Al-Khaṭṭāb." I asked: "And who are these killers of the prophets in every era?" He said: "They are those who falsely claim our loyalty (Walāyah) and are not from us. Upon them is the curse of Allah and the curse of the cursers."2
Al-Farazdaq said: Our Master Al-Ḥusayn (may his glory be exalted) met me on my return from Kūfah, and he said: "What is behind you, O Abū Firās?" I said: "Should I tell you the truth?" He said: "I want the truth." I said: "As for the hearts, they are with you, but as for the swords, they are with Banū Umayyah, and victory is from Allah." He said: "I think you have spoken the truth. People are slaves to money, and religion is a mere utterance on their tongues. They protect it as long as it sustains their livelihoods, but when they are tested by trials, the truly pious are few."3