The power of the tongue.
v.20 Fruit of the lips. From the fruit of the lips the stomach is satisfied (that is you will eat your own words, an oxymoron). If you speak with wisdom you will be satisfied with good things (see also 12:14).
v.21 Life and death. Life and death are in the power of the tongue and we will eat of the fruit thereof (good or bad). See 13:3. The ability to control one’s tongue is a mark of wisdom.
v.22 Wife. Finding a wife is a good thing (see 12:4) and the one who finds her obtains favor from the Lord. Prv 8:35 says that he who finds wisdom obtains favor from the Lord. See also 31:10. A good marriage is a gift from above.
v.23 The poor and the rich. The poor man pleads for mercy, but the rich man answers harshly. The verse observes that poverty and riches cause conflicts between people.
v.24 Many companions. A man of many companions may come to ruin but there is a friend that sticks closer than a brother. See 17:17. Choose your friends carefully.

Read Proverbs 18:20-24