Throughout the two thousand year history of the Christian church it has been widely accepted that God's revelation to man is complete, contained solely within the sixty six books of the Old and New Testaments. However there have always been those at the periphery of 'Christianity' who have held a different viewpoint, believing that God continues to speak to man outside of Scripture. The Church of Rome has in a sense taken this view, partly by adding the authority of church tradition to the authority of Scripture but also by accepting the dreams and visions of its mystics as being a revelation from God. The cults have likewise rejected the sufficiency of Scripture with Joseph Smith claiming divine revelation for the Book of Mormon. Indeed most cults include the belief that their leader has received a new 'revelation' from God.
Generally the views held by these groups have not posed a significant threat to evangelical Christianity for most believers reject the claims of Roman Catholic mystics as well as cults such as the Mormons and Jehovah's Witnesses. The danger today in relation to extra biblical revelation and the sufficiency of scripture (and it is a very real danger) is found elsewhere, specifically within the Charismatic Movement. The shelves of most Christian bookstores are filled with the titles of bestselling authors who claim to have received a message from God. Books such as 'Heaven is for Real' have been made into films, and have found great popularity amongst many Christians, yet they are based entirely on the belief that God continues to reveal additional truth outside the Holy Scriptures. The words which emmanate from the mouths of many preachers are no longer preceeded by 'the Word of God says', but more often it is 'God told me' which we hear.