Sin is bad but covering sin is even worse. If deliberate sin is like putting oneself in jail then covering such sin is like throwing away the key. The covered sin, the one a man attempts to hide and refuses to confess, shuts one off from spiritual prosperity and divine mercy. "He that covereth his sin shall not prosper, but whoso confesseth and forsaketh sin shall have mercy" (Prov. 28:13). There can be no trading on God's mercy because it does not ignore sin. It is not a question of whether His mercy saves the sinner; but whether the sinner will allow it by confessing and forsaking his sins. In covering sins the sinner spurns the mercy through which forgiveness and salvation are possible. If a merciful God provides the feast, sets the table, and invites all to partake, then how can He be faulted by those who choose to starve themselves? No, the Lord's hand is not shortened, that it cannot save, neither can limitations be placed on his mercy - except by the rebellious sinner who refuses it. What sin could be more pernicious than the one a man will not acknowledge nor repent of? Little wonder God says such an one shall not prosper.
But not only does the covering of sin preclude forgiveness, it easily becomes the launching-pad for yet other sins. Nothing encourages sin like sin. Lies and deceitfulness are popular camouflage for hiding evil. This in turn leads to the development of a compromising attitude toward all sin, both in self and others. The unwholesome attitude that permits one sin will soon permit another. Why? Because it involves more than one's disposition toward a certain unlawful act; it involves his attitude toward God Himself - the One whose law is violated! When tempted by Potiphar's wife Joseph reminds her of his obligations to his master then asks, "how then can I do this great wickedness, and sin against God?" (Gen. 39:9) To wrong his master was bad; to wrong God was worse. How men need Joseph's perspective of sin - and regard for God. Ungodliness (Gr. asebeia) is essentially a wrong attitude toward God, the expression of which is lawlessness (Gr. anomia) which is sin (2 John 3:4, see Vine's on "ungodliness"). In view of this, no sin can be considered as isolated or insignificant. (Notice carefully James 2:10-11 in this connection, especially "For He that said...", v.11) One just as well talk about the size of God as to make distinctions in sizes of sins for the deliberate practice of sin constitutes a rejection of Him and His law (1 John 3:4; 1 Thess. 4:8). It is not difficult to understand why no man can prosper while perpetuating disrespect for God in the covering of sins.
Finally, and logically, the practice of covering sins has the effect of hardening the heart (Heb. 3:13). How could it be otherwise when one persists in violating a truth-trained conscience? Who could court such ungodliness without a corresponding adverse effect on the inner man? "Can a man take fire in his bosom, and his clothes not be burned?" (Prov. 6:27) Surely anything that can so harden a man's heart while causing him to dishonor God and shun His mercy is a dangerous sin. It may be that the worst sin is to hide sin.
- Plain Talk, January 1974