Arbaeen Hosseini is famous for the 40th day of the martyrdom of Imam Hussain (peace be upon him) and his faithful companions, which coincides with the 20th day of the month of Safar.
According to some reports, the prisoners of Karbala went to Karbala on the 20th day of Safar 61 AH on their return from Syria to visit the grave of Imam Hussein (peace be upon him) and other martyrs. However, some scholars such as Sheikh Tusi and Sheikh Mofid believe that the captives went from Syria to Medina; Also, some scholars, writers and Muqatil considered it unlikely that the captives arrived in Karbala during the first Arbaeen of Hussain and rejected the traditions and evidence in this case. However, Jabir bin Abdullah Ansari’s arrival in Karbala in Arba’in and the visitation of that Prophet, there is not much difference between the sources and the tradition of Arba’in pilgrimage was established by him.
Arbaeen pilgrimage is one of the recommended actions of this day and according to a narration from Imam Hassan Askari (peace be upon him), it is considered one of the signs of a believer. Shiites mourn on this day. The Arbaeen walk to Karbala is one of the largest mourning ceremonies and one of the largest religious gatherings in the world.