(28) A lying tongue hateth those that are afflicted by it; and a flattering mouth worketh ruin.
King James Version
Clearly, lying is an act of hatred. It is so bad that it can bring ruin to those it is used against, and like a boomerang, it will return to destroy those who employ it.
Here is a good maxim to live by: Never believe anything bad about a person unless you know it to be absolutely true; never even tell that absolute truth to another unless it is absolutely necessary; and remember when you do tell it, God is listening.
Galatians 6:7-8 contains an important principle: "Do not be deceived, God is not mocked; for whatever a man sows, that he will also reap. For he who sows to his flesh will of the flesh reap corruption, but he who sows to the Spirit will of the Spirit reap everlasting life." All who believe God must deal with this reality. God cannot be fooled. Neither can God's law be fooled, just as the law of gravity cannot be fooled. A person cannot treat God or His law with contempt and get away with it. We are accountable to it whether we wish to be or not.
This principle teaches that what a man does to life, life does back to him. It is inescapable. "Do men gather grapes of thornbushes or figs of thistles?" Jesus asks (Matthew 7:16). The hypocrite cannot fool God's laws, only other people—and himself—for a while. This principle is instructing us not to delude ourselves into thinking that we will somehow escape its power. We must always strive to live the truth, which is a difficult job considering the heart within.
The prophet writes in Jeremiah 17:9, "The heart is deceitful above all things, and desperately wicked; who can know it?" The Hebrew word translated deceitful can mean in this context "faithless, insincere, hypocritical, underhanded, false, dishonest, treacherous, sneaky, double-dealing, tricky, cunning, and crafty." They all apply.
The phrase desperately wicked, which can also be rendered as "perverse" or "incurable," implies that the heart knows better but does it anyhow. It is addicted to deceit or faithlessness! Who can fathom its treachery or corruptness? We know where this came from! "The prince of the power of the air" is largely responsible for this evil proclivity because his spirit dominates life in this world (Ephesians 2:2; II Corinthians 4:4; Revelation 12:9). He was a liar from the beginning (John 8:44), deceiving himself into believing that he could overcome his Creator (Isaiah 14:12-14)!
Solomon says in Proverbs 11:9, "The hypocrite with his mouth destroys his neighbor, but through knowledge the righteous will be delivered." This proverb comforts Christians by reminding us that we have a hedge about us. It also reminds us that, eventually, truth will out. The flipside of this is that the lies, too, will be exposed and with them the condemnation of the liar. Why is this certain? Because there is a God in heaven overseeing His children's well-being.
— John W. Ritenbaugh