If we do not adhere to the original, then we have a very perverted, false counterfeit. The Gospel of Jesus Christ is not whatever some apostle or prophet suddenly wants it to be. Charismatics have created a counterfeit faith that saves nobody. And they prevent seekers from getting saved. A horrible reality.
The New Covenant did not abolish any previous covenants of God
Later covenants of God did not invalidate former covenants! The New Covenant was a fulfillment of former covenants. Invalidate the Old? The logic isn’t even there – so how do so many people believe the false teachers?