Since the fool has a basic belief that God doesn’t exist sin becomes a game to him. Mischief refers to evil, wrong, or harm. The basis of the word is shameful behavior from wickedness to adultery.
Not only does the fool do mischief but it is like a sport to him. It is fun, causes him laughter, pleasure, and the making fun of right and truth. It is like everything is a big joke.
Fools make fun of anyone calling something a sin. To them sin is funny and to be brag or boast about committing the sin. This word sin means doing wrong but also is used to refer even to the sacrifice made for sin. In other words that would mock the sacrificial death of Jesus on the cross for our sins.
You can’t convince the fool that he is wrong or doing wrong. He is so sure of himself. In his pride he fully thinks he is right. For the believer it is not about what is right in our eyes but in the eyes of the Lord Jesus and the Word of God.
So you shouldn’t get into arguments with the fool or about his foolishness. He just uses the argument to solidify his position. Don’t waste your time arguing. No casting the pearls before swine. Someone said that if you fight with a skunk even if you win you still stink. So it is best just to stay away from the argument.
Now the very next proverb says that you should answer the fool. So you will have to use discretion. He needs to be shown the truth but only so that he knows that you are not in agreement and accepting of his foolishness.
So be wise. Don’t be pulled into traps where the fool just wants to use you to mock sin and right.
Even if you seemingly won the argument and the fool apparently left his foolishness the true fool will head back to his vomit.