Proverbs 12:20

Deceit is in the heart of them that imagine evil: but to the counsellors of peace is joy.

Deceit is in the heart of those who imagine or plan evil, taking root within those who devise harm. It is not limited to lies spoken aloud but includes evil thinking in the heart. Such evil thinking is guile, and unrighteous thoughts are sin because they transgress God's law and come under its judgment.

Ill-will leads people to put a false construction on another's actions and to spread damaging reports. Good-will, which regards another's rights as one's own, helps prevent false witness, though it does not always ensure a fully balanced or accurate account. In contrast to those who plan evil, whose hearts contain deceit, joy belongs to the counselors of peace.