Pursue righteousness.
v.20 Precious treasure. The wise man has precious treasures in his house; but the fool devours all that he has. See 10:16. The wise accumulate wealth while the foolish squander it.
v.21 Pursue righteousness. If you pursue righteousness (and wisdom) you will find life, righteousness (or prosperity), and honor. See Mt 5:6 for Jesus’ teaching on this. Only the Lord can grant a person life, prosperity, and honor.
v.22 Stronghold. The wise man brings down the stronghold of the mighty city. Wisdom is better than military power (Eccl 9:13-18).
v.23 Tongue. You will keep out of trouble if you bridle the tongue (keep your mouth shut). Similar idea on controlling tongue at 13:3 and Jas 3:2. The ability to control your tongue is a sure mark of wisdom.

Read Proverbs 21:20-23