There is a promise from God that the wise will be crowned with riches. Some take this to mean only financial riches. The problem with this view is that many a godly, wise man or woman did not grow rich with money - but would argue to their death that they were rich in ways that a wealthy man would never understand. That is the key to understanding the proverb for today.
When a man acts wisely, he will be blessed in business endeavors. His wisdom will guide him into good practices that will yield sustainable financial growth and blessing. Wisdom will keep him from ungodly habits that rob a man of his wealth - as well as help him form habits that will prove very financially profitable to him. It was the wisdom of Joseph that kept Egypt from being devastated from seven years of famine that came to them. That wisdom led them to not sqander the years of blessing that God gave them. They saved instead and prepared for leaner times that would come. Wisdom is what leads us in this way. Wisdom also leads us to abandon addictive activities that rob us of wealth. A wise man does not engage in gluttonous and addictive habits like smoking, drinking, taking illegal drugs or overeating - not just because of the health problems such lifestyles pose. They also avoid these things because they have a tendency to cost a great deal financially as well. The hard working mindset of the wise man also prospers him and causes him to be blessed financially. All these things as well as hundreds more bless the wise man.
The wealth that a wise man gathers is more than financial though. He embraces wisdom because he embraces God. The wealth that comes to him initially manifests itself through the gospel. He receives the grace of God - and learns that this makes him wealthy beyond imagination. He rejoices in God more than in mere financial riches. This gives him the precious jewel of contentment - which makes him richer still. Being content in God, he knows a sense of blessing no matter whether he has little or much in this world. He has fellowship with Almighty God - and a future promise of an eternity enjoying Him in heaven. Knowing this makes him rich even if he has nothing - and causes all who watch him to covet the joy and peace that reigns in his heart.
The fool only knows his folly. The interesting thing about this second phrase in verse 24 is that all the fool gets for his folly is more foolishness. The word in Hebrew here is "ivveleth" which means foolishness or folly. We don't really get the idea of what the fool is doing and getting here until we look at the root of these two words. The root word for folly and for foolishness used in verse 24 is "ewiyl." The word means a foolishness that hates wisdom and morality. Hence this man walks in a way that despises God's counsel - and that embraces a worldly morality that rejects God's commands. In the end, this fool will only get his fill of his own ways. One of the Hebrew targums on this verse teaches us that when the fool acts according to his foolishness, he is not rewarded with riches - but with only a wealth of his own foolishness. In truth - the fool gets nothing for his foolish behavior. He receives only more foolishness and deeper bondage to his ungodly actions.
This may be hard to understand, but let me conclude the comments on today's proverb with two examples. The fool acts with folly - and gets more foolishness for it. The heavy drinker drinks himself into a stupor. The drug addict gets high. The sex addict looks at his online pornography or engages in prostitution. Each of these fools acts foolishly - and what they get for their actions is a deeper desire for more. They don't ever get anything except a short-lived thrill for their folly. The wise man acts according to God's wisdom and moral law and receives riches for his actions. His work ethic yields wealth for him. His choice to avoid sexual immorality will yield a happier life with the wife of his youth. His choice to avoid the excesses of the party life will yield two things. First, he has a morning without the hangover or the downer from his high. Second, he will live a far more healthy life because he avoids these things that destroy our physical bodies. The wise man is crowned with a wealth of unwasted money, undamaged health, and one other thing more valuable than all else. He winds up with uninterrupted fellowship with His God.