In the history of Islam, there is no instance when any Infallible Imam (a.s.) had ever attacked first on any suspected enemy in either open encounter or from a hiding place. The Commander of the Faithful Imam Ali (a.s.) never attacked an enemy who was disarmed or unable to defend himself. He gave clear instructions to the Muslims in the light of the Glorious Qur’an, never to attack women, children, disabled, sick or one who run away from the battlefield. This principle saved the lives of Abu Sufiyan and Muawiya who ran away from the battlefield during their fight against the Noble Messenger (s.a.w.a.s.). The King of Martyrs Imam Husayn (a.s.) followed his grandfather and father during the entire course of events leading to the greatest tragedy in human history-Karbala. During this period, many of his friends offered to accompany him, the Imam dissuaded them saying that Yazid was after his blood.

 The Makkans received him with great love and reverence and gathered around him for guidance. The Imam’s chief aim was to train people to be pious and God-fearing and strictly follow the Islamic practices. While he was still in Madinah, he had received hundreds of letters from Kufans, which increased to 12,000 after the death of Muawiyah. They complained about the oppressive, vicious and merciless killing of innocent people by the governor of Basra, Ibn Ziyad. The letters emphasized that they were left without an Imam, and as the Imam of the time it was incumbent upon him to come to the rescue of the oppressed and to render justice, and if he failed to do so, he would be responsible before God.

Imam Husayn (a.s.) replied to their appeals and told them that he was sending his trusted cousin Muslim bin Aqil to let him know the real affairs in Kufa and that the people were unanimously petitioned that they were without an Imam for guidance. Further he was not planning to come as a conqueror but as an Imam fettered by the chains of Divine laws to act justly and righteously. He was not an opportunist to empower himself with the support of the disgruntled and impatient masses.

 At Mina, Imam Husayn (a.s.) gave a sermon: “You are fully aware of the tyranny and oppression of Mu'awaiya and Yazid. By God and the close relationship between me and the Messenger of Allah, I ask you to bear witness to what I shall say, and to write it down and propagate my speech to everyone in your city. I apprehend that the truth will be buried and falsehood will be made to prevail. Is not Muhammad the Messenger of Allah? Is not Fatima the only child of the Prophet and Chief of the women in Paradise? Is not Ali the cousin and deputy of the Prophet? Have you not heard that the Prophet say, when he created brother hood between his followers that Ali was a brother to him like Aron was to Moses? Am I not the son of Ali and Fatima? Have you not heard that the Prophet say that I and my brother Hasan are the masters of the youth in Paradise? Is it true that when the Prophet constructed the mosque, he had all the doors closed except the one leading to the house of Ali and Fatima, and when Umar wanted to open a chink in the wall of his house so that he could peep into the mosque, the Prophet sternly forbid it? Is it true that on the day of Mubahila with the Christians, the Prophet took my mother Fatima to represent women, my father Ali to represent men and I and my brother Hasan to represent the children of the Prophet? This the Prophet did in accordance with what was revealed to him by God. Have you not heard the Prophet say that ‘Fatima, Ali, Hasan and Husayn are from me and I am from them’ and ‘they are my Ahlul Bayt’? Have you not heard the Prophet say that one who loves my Ahlul Bayt loves me and one who loves me loves Allah, and he who opposes my Ahlul Bayt opposes me and one who opposes me oppose Allah’?” The people said, “We affirm the truthfulness of what you said.”

The Imam (a.s.) said, “I make it obligatory on all of you gathered here to repeat all what you have heard from me now, to your kith and kin, friends and acquaintances, in villages, towns and cities and wherever you find two believers gathered in one place.” 

 Source: The Hidden Truth about Karbala by A.K. Ahmed