The fear the Lord.
v.16 Avoid evil. A wise man is cautious (or fears the Lord, NIV) and shuns evil, but a fool is reckless and careless (and yet feels secure). The wise consider a matter while the fool simply reacts. See Phil 2:12.
v.17 Bad character (traits). Those with a quick temper acts foolishly (stupidly). A man of evil devices is hated. Evil devices refers to evil that has been carefully planned (schemed). Both the man of quick temper and the evil schemer lead to bad ends. See 12:2.
v.18 Knowledge. Here the prudent have (are crowned with) knowledge and the simple inherit (the shame of) folly.
v.19 Reward of the righteous. Evil men will bow down to (acknowledge and serve) the righteous. See Phil 2:10. The long run result of this principle is illustrated in Lk 16:19-31.
v.20 Popularity of riches. The poor are disliked by their neighbors while the rich are popular. Jesus said anyone in need is our neighbor, Lk 10:25-37.
v.21 The needy. He who despises his neighbor (who is needy) is a sinner. The one who is kind to the needy (neighbor and friends) will have God’s blessing (and be happy). Love your neighbor as yourself, Lev 19:18.
v.22 Conduct. Contrasts devising evil and devising good. Those who do the former go astray, while the who do the latter show (or find) steadfast love and faithfulness.
v.23 Hard work. In all hard work (toil) there is a profit, but mere (foolish) talk leads to poverty. Be more afraid of idle talk than of hard work. Talk is cheap but action leads to profit.
v.24 Wealth. The crown (symbol of honor) of the wise is his wealth, while the wealth of the fool is his folly (nothingness).
v.25 Truthful witness. This proverb contrasts truthful and false witnesses (in court). The truthful witness saves lives, the false witness is deceitful (and destroys lives). See 14:5.
v.26 Security. He who fears the Lord is secure and his children have a refuge (a secure fortress/confidence).
v.27 Fountain of life. Reverential fear of the Lord is a fountain of life, turning a man away from the snares of death. See 13:14.
A wise man cautiously considers his steps. He is characterized by the fear of God which leads to life and security for him and his family. Quick-tempered fools alienate God and people they come into contact with.