Sanctification, according to this perspective, is not progressive because the inner man is already created in true righteousness and holiness.
The argument against progressive sanctification is rooted in the belief that the inner man, which is regenerated in Christ, is already made perfect in righteousness and holiness. This means that while believers may struggle with sin in their outward flesh, the inner man does not sin and cannot become more righteous or holy. The inner man's state, being in Christ, is fixed and does not fluctuate based on behavioral performance. Hence, the focus of sanctification should not be on the outward man's improvement but rather on the believer's identity in Christ, which secures them entirely from condemnation and allows them to walk in the Spirit, reflecting the reality of their new creation status.
Commentary