“Unbroken patterns of sin are characteristic of the unregenerate. No matter what a person claims about being a Christian, if he or she continues in sin, it is only a claim and not a reality. When you became a Christian, the pattern of sin was broken and a new pattern came into existence. Godly desires took over. Does that mean there’s no sin in your life? No, because your unredeemed flesh is still there. But the more you pursue those religious affections, the less you will sin. … Sin as a life pattern is incompatible with salvation. That’s because to experience salvation is to be saved from something, and that something is sin. If a person could continue in sin after being saved from sin, that would mean salvation is ineffective.”
~ John MacArthur, “Saved Without a Doubt,” p. 92.