What does Proverbs 26:24 mean?

This verse further develops a thought begun in the prior verse (Proverbs 26:23). The given metaphor was the glaze covering a clay pot: it may be attractive, but it's just a thin disguise. What's underneath is not as valuable, or as pretty. A person who puts on a show, trying to fool others, but who is evil in the heart, is in the same spiritual state. Jesus criticized "hypocrites," who say one thing while believing something else, using related imagery (Matthew 23:25). The Greek term translated "hypocrite" is closely related to the term for an actor: a person who pretends.

Some disguise their hate and malice using careful words. They give the impression of being calm, or kind, or reasonable. A classic example of this is Judas's kiss, which appeared to be friendly, but was an act of betrayal (Luke 22:47–48). A graphic example of "disguised lips" comes from Joab and Amasa, in 2 Samuel 20:9–10. Joab politely spoke, and moved as if he were greeting Amasa, only to deliver a gruesome, fatal wound.

The next proverb continues to warn against such people. If we have reason to think someone is malicious or hateful, we should be very suspicious of their words (Proverbs 26:25). Eventually, the veneer will crack, and others will find out the truth (Proverbs 26:26).