Here’s a great analysis of a particularly destructive error gaining some traction within certain parts of the Christian community, the heresy of eternal justification.
In light of eternal justification, the elect of God were never under the wrath of God. Therefore, they cannot be any time under the federal headship of Adam. This implies no spiritual commonality of any kind with the reprobates. Now, Christianity teaches that all humans are all united in the fact that we are all sinners, and it is only because of particular grace that I as a sinner am saved out of my sin and out of the hellfire I justly deserve. Advocates of eternal justification however logically should deny this. With no spiritual commonality between the elect and reprobates (constituting a denial of the Imago Dei to some extent), the two are as light and darkness. No longer are Christians to be considered as undeserving sinners saved by God’s amazing grace, but as saints who happen not to realize that they are already justified. (This of course will logically lead to various forms of Antinomianism but we will not go there).
This rings a bell with me in particular, as this error was part of the trouble that we ran into in our church as well. So I appreciate this very solid analysis.
This doctrine is fundamentally a denial of justification by faith alone. It teaches that the elect is already justified without exercising faith- faith is just the point at which the believer becomes subjectively aware of their justification.