In the Glorious Qur'an verse 59 of Surah An Nisa, Allah (SWT) says:
"O you who believe! Obey Allah, and obey the Messenger and "Ulil Amr" (Those who are authorized to command) from among you."
The believers always obey Allah (SWT), obey His Messenger and the "Ulil Amr" appointed by Him. It is an open invitation. Because, Laa Ikraaha Fid Deen [There is no compulsion in religion] (Surah Al-Baqarah, 2:256). Those who (in truth) are not believers can do what they want.
Likewise Prophets, Messengers, sent down by Allah (SWT) to guide and warn people, never accepted anyone at all as Prophet or Messenger, whatever the circumstances were, be it that they did not stop claimers of this kind, or opponents, with application of force or repression.
In the same manner Imam Ali Ibn Abi Talib (A.S.) did not recognize anyone as "Ulil Amr". His elder son Imam Hasan (A.S.), like his grandfather, the Holy Prophet Muhammad (S.A.W.) as in the [Treaty of Hudaybiah], let Muawiyah ibn Abi Sufyan be the ruler, but did not give up his rights of the "Ulil Amr", which he was at that time.
When Yazid ibn Muawiyah became the ruler he threw to the wind the earlier policy of the rulers not to demand "Bayah" (oath of allegiance) from the children of the Holy Prophet Muhammad (S.A.W.), and began to exercise pressure upon Imam Hussain (A.S.) to swear loyalty and acknowledge him as the "Ulil Amr", which the Holy Imam rightly refused. It is another aspect of the whole affair that Yazid ibn Muawiyah was the meanest tyrant of the worst degree, but even if he was an ordinary ruler Imam Hussain (A.S.) could not swear loyalty to him as the "Ulil Amr". So he did not. In the month of Rajab al-Murajab 61 Hijrah, he left Medina and went to Makkah. From Makkah, before performing Hajj Pilgrimage, he took his family with him, and with some friends and companions, true believers, he began the journey towards Iraq, with the expressed intention to cross the boundaries of the empire under the rule of Yazid ibn Muawiyah, and settle down in some other country, Iran or India, because he wanted to make it clear to Yazid ibn Muawiyah that he could not allege obedience to a "non-Ulil Amr" as he himself was an "Ulil Amr".
It was not to be. A large army of Yazid ibn Muawiyah under the command of Umar ibn Saad surrounded the caravan of Imam Hussain (A.S.) when he reached Naynawah, Karbala, on the 2nd of Muharram Al-Haram in 61 Hijrah.
There are several other aspects of human relationship and behavior in the events of Karbala that took place in the 10 days of Muharram-ul-Haram, culminating in the Martyrdom of Imam Hussain (A.S.), and his 72 friends and relatives, which come into sharp focus as we recount every minute, during the religious gatherings, each year, but, above all, the ultimate reason remains the same, the impossibility of taking "oath of loyalty" (Bayah), by an "Ulil Amr", to obey a "non-Ulil Amr".
After Imam Hussain (A.S.), all his successors to "The office of the Ulil Amr", our holy Imams, refused to obey "Non-Ulil Amr", and every ruler held each of them prisoner, used every trick, applied force and in the end killed every Imam, exactly as Yazid ibn Muawiyah did.
Muharram-ul-Haram is a month of mourning for the lovers and followers of "Ahlul Bayt or Aal-e-Muhammad". In this month, on the 10th day (Ashura) in 61 Hijra, Imam Hussain bin Ali (A.S.), the grandson of the Holy Prophet Muhammad (S.A.W.) and the younger son of Imam Ali and Fatima Zahra (S.A.), together with his family and friends, in all 72 men, were slain on the sands of the desert of Naynawah, Karbala. Since then, each year, the true followers of the Holy Prophet Muhammad (S.A.W.), through grief, sorrow and tears, keep alive the message, cause and purpose of the greatest martyrdom in human history.
No doubt Muharram-ul-Haram is a holy and sacred month:
The believing men and women, in this month of Muharram-ul-Haram, suspend application of good effects of days and dates and avoid rejoicing even if happy events come in their stride.
The friends and followers of "Aal-e-Muhammad" hold meetings (Majlis), they had been doing so, for last fourteen hundred years, in the name of Imam Hussain (A.S.), during the months of Muharram-ul-Haram (and Safar al-Muzaffar), particularly in the first 10 days of Muharram-ul-Haram, to give new life to the Divine Message of "Laa Ilaaha Illallah (no one worthy of being worshiped but Allah)" as the beloved saint poet of the Indian subcontinent, Khwaja Moinuddin Chisti (of Ajmer) had said: "Indeed Hussain (A.S.) is the architect of 'Laa Ilaaha Illallah' both are reciprocally related to each other."
And the philosopher poet of Pakistan, Dr. Muhammad Iqbal, had said: "Ismail was the beginning (first step), Hussain was the ultimate."
Each year (at the advent of Muharram-ul-Haram) Islam turns over a new leaf.
In fact it is on account of Imam Hussain's remembrance, every year, we know who the Holy Prophet Muhammad (S.A.W.), Imam Ali Ibn Abi Talib (A.S.), Fatima Zahra (S.A.) are, and what were their true substance, style and wisdom.
It is because of Imam Hussain's memory, we call to mind each year the Islam, and it becomes clearly visible from behind the blur of the dust of delusion, thrown into the eyes of Muslims in the name of Muslim rule.