“Let a bear robbed of her whelps meet a man, rather than a fool in his folly.”
The Bible calls many people "fools." A fool says in his heart that there is no God. A fool builds big barns and isn't rich towards God. A fool makes a mock at sin, and a fool has no fear of God before his eyes. It is because of that you don't want to mess with him. A bear robbed of her offspring is pretty scary. She will rip you in pieces, so what does this verse mean?
A person who has no fear of God will lie to you, steal from you, and even murder you if he thinks he can get away with it.
The common denominator in every murder case that has taken place in history has been a lack of the fear of God. Those who fear God won't so much as hate someone, because they know that God equates hatred with murder, and that they have to face Him on Judgment Day.
Such sobering knowledge helps sin-loving sinners flee to the Savior, and keep their hearts free of sin.