Read this article by Peter Best, accusing John Piper of not being truly Reformed. His conclusion?
There are other significant changes but, to sum up, John Piper, wittingly or unwittingly, is taking his followers down a different path from that trodden by the Puritans of old. His theology is not orthodox, being a deviation from Scripture. His enthusiasm, winsome ways and plausible writings have already won over some who should know better. But he is not a safe guide. We do not need John Piper to reshape truth. We have our Westminster standards. They do not need improving.
Every religious group/denomination/movement must have boundaries. Some want the boundaries to be tight. Others want a big tent. The “Reformed” tent is rather large, in my estimation – although there are some who would love to close the borders completely.
What does this teach us about John Piper? Not much. I’m still a fan.
What does this teach us about us Fundamentalists? As I’ve said before, we’re inclined to keep narrowing the parameters of fellowship until we’re the only ones who are “right” on anything. Let’s stay united on the fundamentals and avoid the sectarianism that so often qualifies our discourse.