What is KJV Onlyism?

KJV Onlyism, as the name suggests, is the belief that the King James Version is the only true translation of the Bible. There are varying degrees to this. Some KJV Onlyists are only a step above people who simply prefer the KJV, whereas others will consider you an apostate if you use any other translation. KJV Onlyism is an unnecessarily divisive, and thus a very dangerous doctrine. While there is nothing wrong with having a particular preference for the KJV, or even using it exclusively, it becomes a problem when it affects your view of, and relationship with fellow Christians. Furthermore, when you make it a Gospel issue, you are altering the Gospel itself, and thus are to be considered anathema.