Therefore if a man claims to have received a revelation of some fresh truth we should suspect him immediately.

Again, we must note that often in the history of the Church trouble has arisen because people thought that they were prophets in the New Testament sense, and that they had received special revelations of truth. The answer to that is that in view of the New Testament Scriptures there is no need of further truth. That is an absolute proposition. 

We have all truth in the New Testament, and we have no need of any further revelations. All has been given, everything that is necessary for us is available. Therefore if a man claims to have received a revelation of some fresh truth we should suspect him immediately.

- D. Martyn Lloyd-Jones

Christian Unity