This
Islam, or radical interpretations of Islam, acts as a perpetuator and gives direction to violent tendencies, but those are in 99% of the cases already existing, and not an autonomous creation or consequence of Islam.
And concerning the discussion about Christianity and the two testaments, it is theologically rather broadly accepted that the New Testament, and especially the four canonic gospels about Jesus are the ultimate foundation of the religion in terms of scripture. The whole religion evn in name is based on Christ afterall, and the teachings of him are what essentially seperates them from the Jewish faith (on a very basic level). What's interesting here is that even for me as an atheist, Jesus the way he is desribed in the gospels is a pretty great man and rolemodel. He is very expressive about the virtually absolute and complete banning of violence, and of course very adverse to selfishness and egoism. Yet, a sheer uncountable number of his followers have found equally countless ways to utilize him to justify violence and egoistic actions and ideas, starting of course already with the apostle Paulus (who is a rather interesting semi-historic figure in my eyes, and probably responsible for Christianity actually being something larger than just a minor Jewish sect), up to the at times simply moronic understanding of Jesus and his teachings in certain US-American conservatives.