Fanaticism

Fanaticism... is a terrible danger which we must always bear in mind. It arises from a divorce between Scripture and experience, where we put experience above Scripture claiming things that are not sanctioned by Scripture, or are perhaps even prohibited by it.
But there is a second danger and it is equally important that we should bear it in mind. The second is the exact opposite of the first, as these things generally go from one violent extreme to the other. How difficult it always is to maintain a balance! The second danger, then, is that of being satisfied with something very much less than wheat is offered in the Scripture, and the danger of interpreting the Scripture by our experiences and reducing its teaching to the level of what we know and experience; and I would say that this second is the greater danger of the two at this present time.

D. Martyn Lloyd-Jones, When The Spirit Comes With Power, p. 55