21-23 There are many plans in a man’s heart - but it is the Lord’s purpose that will prevail. A desirable trait in a person is loyalty. It is better to be poor than a liar. The fear of the Lord  leads to life. One who has it rests content. He will not be disturbed by trouble.

24 A lazy person buries his hand in the dish, but he does not even bring the food up to his mouth. 25 Strike a scoffer, and an undisciplined person may learn caution. Warn a person with understanding, and he will gain knowledge.

26 A son who attacks his father and chases away his mother brings shame and disgrace. 27 If you stop listening to discipline, my son, you will stray from the sayings that give knowledge. 28 A malicious witness mocks justice, and the mouth of the wicked swallows evil. 29 Punishments have been prepared for scoffers and beatings for the backs of fools. Proverbs 19: 21-29 Evangelical Heritage

There's a frequently heard quotation which says “those who don't learn from history are doomed to repeat it.” While it's usually applied to a nation making the same terrible mistakes other nations made which led to their decline, it can apply just as much to people who are unwilling to learn from warnings or punishment. That seems to be the implication of vs 25 and vs 27.

The word 'undisciplined' in vs 25 can also mean 'inexperienced'. Some people can learn to avoid doing wrong if they see those who are doing wrong being disciplined. Sadly, there are many who are not deterred even by seeing people punished for crime. They are the sort of people described in vs 28. They just never learn.

On the other hand, verse 25 also tells us that people with good sense and understanding don't need to see or receive any punishments. Simply warning them of the danger of foolish actions is enough to make them choose the right way. But even they need to take care. What does the writer warn such people of in vs 27?

There is always the possibility that someone who usually chooses what is right in life growing tired of doing good! Wrong things can begin to look tempting and a person can grow envious of wrongdoers. It may look like they are having 'much more fun' in life. The writer warns of the danger of straying from teaching that gives knowledge. If a Christian starts getting tired of living a disciplined life he or she will stop reading the Bible and perhaps stop going to Church. It's a very sad sight to see people who once appeared to be walking in step with the Lord losing the plot and bringing great sorrow into their lives.

What are the blessings of keeping in step with the Lord according to vs 21-23?

Such people have the confidence that in all the plans they make (many of which may come to naught) the Lord will still work His purposes out. Not just in the world, but in their personal lives as well. They also know that wealth and possessions mean nothing if there is no integrity in one's life. And they know that a God fearing life leads to great security. It's been said by someone that if you have a true fear of God, you have nothing else to fear. That's not meant to be a glib statement. Life can bring some stressful and frightening situations. But the believer can draw strength from the knowledge that Jesus is with them.

What is one of the reasons why some people are not willing to learn according to vs 24?

It's a case of 'we can't be bothered'. There is a mental laziness that is unwilling to take in any good advice. Such people may end up like the disgraceful person described in vs 26. They certainly run the risk of what vs 29 warns. The Bible has many instances of people who feared God, and of people who messed up badly. Happy is the man or woman who learns from such lives to not repeat the mistakes of those who messed up, and follows those who were faithful.