The contrasts in Proverbs 10 continue in verses 17-21.
"Whoever heeds instruction is on the path of life,
but one who rejects a rebuke goes astray."
"Lying lips conceal hatred,
and whoever utters slander is a fool."
"When words are many transgression is not lacking,
but the prudent are restrained in speech."
"The tongue of the righteous is choice silver,
the mind of the wicked is of little worth."
"The lips of the righteous feed many,
but fools die for lack of sense."
Verse 18 is the only verse in Proverbs 10 that does not contain a contrast [scholars call such contrasts "antithetic parallelism"]. This verse is "synonymous parallelism," that is, its two lines proclaim the same truth in different words.
Various statements about the "lips," the "tongue," "speech," "instruction," hold these verses together. What are some of the truths they declare?
1. Like verse 8, verse 17 emphasizes the importance of listening to others, even those who rebuke a person for doing or speaking or thinking wrong.
2. Verse 18 denounces lying and slander. Modern people in and out of the church ignore this godly teaching regularly. May God help us to use our tongues to encourage and affirm others, not to tear them down and try to destroy their character. Paul says in 2 Corinthians 13:10: "The Lord has given me [authority] for building up and not for tearing down."
3. Verse 19 warns against constantly talking, and extols the importance of controlling our tongues.
4. Verses 20-21 declare the effectiveness speech--both good and bad--, and urges us to "feed" those to whom with speak with good words that are uplifting and motivating for good, not with bad words that discourage and motivate to evil.