Why do some Muslims have green flags on top of their houses? A triangular flag with frills at the edges. I have mostly seen these on those from sub continent. Is this a sunnah or a cultural practice?
Well, Shia Muslims Practice this. They usually use green or black flag on their houses. The reason is connected to the Tragedy of Kerbala.
We all know, in Kerbala 10th Moharram, 61 hijri, Imam Hussain, his whole family and companions were killed in desert. The person who was the flag bearer of Imam Hussain was his brother Moula Abbas Alamdar. Alamdar is arabic word means the flag bearer.
While on the tenth of Moharram, the whole family of prophet was thirsty from three days, the daughter of Imam Hussain, Bibi Sakina(5 years old) requested Moula Abbas to bring water from Furat. Moula Abbas after the permission of Imam Hussain went to bring some water. He was himself thirsty for three days, but he did not drink water until everyone else has drunk it. On the way back to tents, he was killed, and the water did not reach the tents.
Relating that Flag of Moula Abbas, Shia's place a flag on their houses to remember the great sacrifice on Ashora.
Green color is used because BANI HASHIM's clan color was Green, as arab clans had different colors for each clan. while black flag resembles the grief.