Arba‘īn

Arba'een (Arabic: الأربعين‎‎, "forty"), Chehlom (Persian: چهلم‎‎, Urdu: چہلم‎, "the fortieth [day]") or Qırxı, İmamın Qırxı (Azerbaijani: امامین قیرخی, "the fortieth of Imam") is a Shia Muslim religious observance that occurs forty days after the Day of Ashura. It commemorates the martyrdom of Husayn ibn Ali, the grandson of Muhammad, who was killed on the 10th day of the month of Muharram. Imam Husayn ibn Ali and 72 companions were killed by Yazid I's army in the Battle of Karbala in 61 AH (680 CE). Writing in forty batches has become a tradition among Islamic scholars.

The reason is the famous saying of Muhammad: "On the day of judgment, among my people, God will consider whoever memorized forty Hadiths as an erudite man". In this regard, numerous Islamic scholars have gathered precious collections that each consists of forty sayings, Hadiths, quoted from the prophet and the following Imams. According to al-Jizzini, the primary martyr, he, too, has written his book Al-Arbaʿūn ḥadīth to practice this narrative of the prophet. Arba'een or forty days is also the usual length of mourning after the death of a family member or loved one in many Muslim traditions. Arba'een is one of the largest pilgrimage gatherings on Earth, in which up to 45 million people go to the city of Karbala in Iraq.

The Arba'een pilgrimage has been observed since the year 61 AH of the Islamic calendar (10 October 680) after the Battle of Karbala or the following year.According to tradition, the first such gathering took place when Jabir ibn Abd Allah, a sahabah, made a pilgrimage to the burial site of Husayn. In fact, Jabir considers as the first one who visited the tomb of Imam Hosein. He was accompanied by Atiyya ibn Sa'd because of his infirmity and probable blindness. His visit coincided with that of the surviving female members of Muhammad's family and Husayn's son and heir, Imam Zain-ul-Abideen, who had all been held captive in Damascus by Yazid I, the Umayyad Caliph. Ali ibn Husayn Zayn al-Abidin had survived the Battle of Karbala and led a secluded life in deep sorrow. He lived under pressure and tight surveillance set by Umayyad Caliphate. It is said that for twenty years whenever water was placed before him, he would weep. One day a servant said to him, ‘O son of Allah’s Messenger! Is it not time for your sorrow to come to an end?’ He replied, ‘Woe upon you! Jacob the prophet had twelve sons, and Allah made one of them disappear. His eyes turned white from constant weeping, his head turned grey out of sorrow, and his back became bent in gloom, though his son was alive in this world. But I watched while my father, my brother, my uncle, and seventeen members of my family were slaughtered all around me. How should my sorrow come to an end?’

...
Wikipedia