It is natural for one that is called and led by God. But he that lacketh these things is blind, and cannot see afar off, and hath forgotten that he was purged from his old sins. A person relying on his nature cannot see through the veil and understand the Word of God. As long as we are still in the flesh we are still confronted daily with man's nature, but Divine nature overcomes it through reasoning. Divine nature has a great deal MORE to do with sharing the truth of the ages and God's overall plan, than it does with sin.
Sin is purged at repentance, but truth is eternal.
Truth is The Promise. Truth is the Word of God. A teacher doesn't have to hammer continously on sin. We know when we have sinned, and so does God. Nevertheless we, according to His promise, look for new heavens and a new earth, wherein dwelleth righteousness.