Both Sunni and Shia Muslims revere Imam Ali (PBUH) as a noble human who is known for his honesty, belief, courage, knowledge, loyalty to the Holy Prophet (PBUH), and devotion to Islam.

Ali ibn Abi Talib is considered by Shia Muslims as the first Imam, the rightful religious and political successor to the Prophet Muhammad (PBUH).

Imam Ali (PBUH) is the only unique personality in the world who was born in the Holy Kaaba in Mecca and was martyred in the Kufah Mosque and was buried in the holy city of Najaf-e-Ashraf in Iraq.
 
He was the first man (and the second person after the Prophet’s wife Khadijah) to convert to Islam after Prophet Muhammad (PBUH) received his divine revelation and declared Islam in public based on Allah’s order. 
During his life, Imam Ali (PBUH) spent much of his time providing for the needs of believers in Mecca, especially the poor, by distributing what he had among them and helping them with their daily chores.

In 623 AD, the Imam married the Prophet’s daughter Fatimah (SA), who gave birth to Imam Hasan (PBUH) and Imam Hussein (PBUH), the second and third Imams of Shia Muslims. 

Imam Ali (PBUH) took part in battles of Badr, Ohud, Khandaq, Khaybar, and many other battles that took place in the early years of Islam.

On the 19th of Ramadan month of the year 40 A.H., Imam Ali came to the mosque in Kufah for his morning prayers. Imam Ali (PBUH) gave the call for prayer and became engaged in leading the congregation.

Abd-al-Rahman ibn Muljam pretending to pray, stood just behind Imam Ali (PBUH), and when he was in a state of prostration, Abd-al-Rahman ibn Muljam, with his poisoned sword, inflicted a deep wound on Imam Ali’s (PBUH) head.
 
Imam Ali (PBUH) suffered from his wound for three days, and he (PBUH) passed away on the 21st of the month of Ramadan at an age of 63 years.

The first Shia Imam was martyred at his finest time - the hour of standing before Allah, on the best of days of the month of Ramadan; during the most glorious Islamic duties, and in the highest and purest divine places, the Mosque of Kufah.

By assassinating Imam Ali (PBUH), the enemies of Islam were seeking to actually assassinate the message, the history, the culture, and the nation of Muslims embodied in the person of Imam Ali bin Abi Talib (PBUH).

The crime of assassinating Imam Ali (PBUH), after centuries, remains one of the cruelest, most brutal, and most hideous acts because it was not committed against one man, but against the whole rational Islamic leadership.

More than 1,400 years later, Imam Ali’s martyrdom is remembered by Shiite Muslims who mourn for him as if it happened yesterday.

During the three days that passed between his stabbing and demise (19 and 21 Ramadan), Shiites hold night vigils.
 
The night before his demise is believed to be one of the three holy Qadr nights, which represent an unparalleled opportunity for Muslims to dedicate much of their time to praying.
 
Throughout the Qadr Night, Shia Muslims recite the holy Qu’ran, hold vigils until dawn, and pray to God while mourning for the martyrdom of their first Imam.
 
The Qadr Night is, in Islamic belief, the night when the Quran was first sent down from Heaven to the world and also the night when the first verses of the Quran were revealed to the Islamic prophet Muhammad (PBUH).
 
The night is described to be better than a thousand months of worshipping.
During the ceremonies held for Imam Ali’s martyrdom, poems are recited and sermons are delivered in his honor since he is one of the most revered figures of Shia Islam.
 
Black-clad mourners from different social backgrounds and age groups congregate in mosques, places of worship, and religious sites nationwide.