I don't believe religion causes violence. Violence is human nature, violence is cause by people with different POV on any topics. Humans are a violent beings, In fact religion was created by someone to restore order to the humans. In fact religion gives a lot of people hope, (but it is false hope) and to me that isn't so bad. but I always find it odd that people quote the bible or the book of Quran, and not notice how ridiculous these stories are.
