Commentaries:
If a person is ever going to change, he must confront his fault, since there is no magic bullet! The proverb's advice can be understood this way: By God's mercy and truth and by our recognition and use of truth, iniquity will be purged because we fear God and submit to Him. One commentator renders the last line of the proverb as, "By loyalty and faithfulness one escapes evil." Another translates it as, "By one's loyalty and faithfulness to God's truth one will escape evil." "Evil" implies the second death. Living the truth does not forgive sin, but it does help to purge the mind of its habitual focus on sin.
John W. Ritenbaugh
The Ninth Commandment
We overcome lying because God mercifully but forcefully brings it to our attention by revealing His truth. When we submit to His truth rather than our self-deceptions, we are beginning to overcome.
Commentators suggest an alternative translation of this verse: "By loyalty and faithfulness one escapes evil." The sense is that loyalty and faithfulness to God's truth are essential elements to escaping the second death. Obeying truth does not forgive sin, but it plays a part in cleaning our minds of the garbage of bad habits lodged in our character so that we are less likely to involve ourselves in sin. God's truth says we must not bear false witness, and that must be obeyed!
John W. Ritenbaugh
The Ninth Commandment (1997)