Actually, that's not an example of Sharia. This is the commemoration of when the forces of the differing branches of Islam (Shiite and Sunni) met in battle back in the 8th century. The Shiites believe that Muhammed's son-in-law was his lawful successor, and the Sunnis believe that one of Muhammed's father-in-laws was the rightful successor. These are Shiite Moslems mourning the fact that on this day they lost the battle for supremacy in Islam, and bloodying themselves in commemoration.