To some others, yet, the most important lesson we can learn from the event of Karbala is its moral or ethical dimension. As Imam Hussain (AS) himself puts: “I seek to enjoin what is good and forbid what is evil and follow the traditions of my grandfather (Prophet Muhammad (PBUH)) and my father (Imam Ali (AS))” .
One of the moral principles that Imam Hussain (AS)’s movement represents and emphasizes is the Golden rule. Based on this rule you should treat others the way you would like to be treated by them: “Do unto others as you would have them do unto you” .
Although it is often said that the term ‘Golden Rule’ first started to be used in the 17th or 18th century , we can also find it much earlier in the words and acts of Imam Ali (AS) and the other infallible Imams (AS). Imam Ali (AS) tells his son Imam Hassan (AS) in his last will that: “like for others whatever you like for yourself, and whatever you dislike happening to you, spare others from such happenings” .
Imam Hussain (AS) also advises people (as a general rule and a decent way of life): “If you do not believe in any religion, at least be free-spirited and honest in your actions” .
Golden Rule as a Universal Moral Law
A newer version of the Golden rule also says: “act only in accordance with that maxim through which you can at the same time will that it should become a universal law” .
So, for an action to be considered morally good, you should ask yourself whether you could always reason or defend it as a universal law. In other words, to be a good person, you must be good for goodness’ sake, no matter what.
Now let’s see how this ethical value was manifested in Imam Hussain (AS)’s conduct.
Imam Hussain (AS), a Perfect Role Model for Humanity
A question anyone might ask after reading about the event of Karbala is ‘why didn’t Imam Hussain (AS) take an oath of allegiance to Yazid to save his life? Why did he choose to be martyred?’ [i]
One clear answer to this question is that he was the perfect leader (Imam) and role model for the Muslim community. A role model is someone who serves as an example and whose behavior is emulated by other people. To be a good role model you have to observe all your acts so that you set proper examples for others to follow.
Now, if Imam Hussain (AS) had pledged allegiance to Yazid’s tyranny, would he be a good exemplar of resistance against injustice for people? Wouldn’t his compromise then make the tyrant ruler more powerful and dominant?
The answer is obvious. Imam Hussain (AS) chose not to follow the indecent tyrant of his time since he intended to act on that maxim he wished it would become a universal law.
Imam Hussain (AS) Would Always Do the Right Thing
On the other hand, some people criticize Imam Hussain (AS)’s decision, saying he could have pledged allegiance to Yazid while at the same time trying to fight him and his injustice over time.
This would also contradict Imam Hussain (AS)’s maxim and is paradoxical, too. In fact, Yazid’s deviations from true Islam and the moral norms were so many that Imam Hussain (AS) could not turn a blind eye to them.
Imam Hussain (AS) did not want to compromise with those so-called Muslims whose behavior and actions had nothing to do with Islam. Instead, he chose to do the right thing, which any free-spirited, wise and virtuous man would do. And with his movement, he invited us all to do the same and follow in his footsteps.
The End Does Not Justify the Means for Imam Hussain (AS)
The other ethical lesson we learn from Imam Hussain (AS) is that he never disregarded human values on his way to achieve his purpose. And he always advised his followers to choose the right way in life. For him, the end did not justify the means. What mattered to him more than anything else was the values not the victory in its apparent sense.
As Imam Ali (AS) says: “The victory achieved through sins is not, in fact, a victory, the one who dominates with the help of evil is defeated” .
It is due to this ethical principle that Muslim ibn Aqil did not kill his enemy, Ubayd Allah ibn Ziyad, before the event of Karbala (before the enemy declared war against them), when he had every chance of doing so in his friend’s house.
He did not kill him because the Holy Prophet (PBUH) forbade any guile: “Verily, Islam became an obstruction of deceit and an obstacle of trickery”  . Imam Hussain (AS) and his companions were seeking to revive the teachings of Prophet Muhammad (AS). So, killing even the most wicked person on earth through deceit, and before he has shown an act of hostility against you, is not compatible with Islamic teachings.
In another account from the event of Karbala, Zuhayr, one of Imam Hussain (AS)’s companions, recommended fighting the enemy when they were fewer in number and so easier to defeat. But Imam Hussain (AS) replied he did not intend to start a war; [he would rather defend if a war was imposed on him].
Imam Hussain (AS) Was Martyred to Preserve Human Dignity
The examples mentioned above manifestly show the behavior of a great role model. Imam Hussain (AS) only wanted to restore what was right, the true teachings of Islam which had been distorted by the tyrant ruler of the time. He tried to preserve human dignity and values.
He could have saved his life as well as that of his family’s and companions’ by accepting Yazid’s allegiance. But this would have been at the cost of ruining their dignity and living a life humiliation. Never would he put up with such disgrace.
So Imam Hussain (AS) made the most of every opportunity to invite people to the righteousness and prevent bloodshed. However, when he was left with two options, humiliation or death, and war was being forced upon him, he chose martyrdom and bravely fought against injustice.
[i] In one of his sermons to people of Kufa, Imam Hussain (AS) said: “Beware! Now this illegitimate son of the illegitimate father (Ubaydullah bin Ziyad) has stationed me between unsheathing the swords or then bear the humiliation, and far be it that we accept humiliation” .
 Biharul Anwar, Vol 44, p. 329
 Harry J Gensler, Ethics, and the Golden Rule, p. 184
 Bihar al-Anwar, vol 45, p. 51
 Allamah Sharif Razi, Nahj al-Balagha, Saying 327
 Tahdhib al-Ahkam, vol. 10, p. 214; Al-Kafi, vol. 7, p. 375