All who are in Christ have the benefits of justification and sanctification. What does this mean, and what is Paul saying about the “old self” and the “new self” in Ephesians 4:20-24?

In 2 Peter 1 the apostle addresses a woeful state of affairs: a worldly, lazy, self-indulgent, and ineffective church in which Christians prefer passing pleasures over the godliness true faith demands. Peter tackles it head-to-head.