The first 2/3 of the Quran is mostly peaceful. This was when Muhammad was in Mecca but when he moved to Medina and became more powerful the messages or Surah he received were of a more evil nature. For example that it was ok to have sexual relations with your captives (aka - rape). Or to not keep any relations with jews or christians, but to ambush and kill them were ever you find them. However this does not make all muslims evil, I know many peaceful muslims who choose to follow only the peaceful surahs.