What does Proverbs 4:19 mean?

In contrast to the blazing light where the righteous walk is the dark path of the wicked. Solomon compares the way of the wicked to deep darkness, and says the wicked stumble over what they cannot detect. Just as light characterizes the righteous and their walk, so darkness characterizes the wicked and their walk. This imagery emphasizes the way sin and spiritual ignorance cause men to become lost, to fall, and to be afraid.

Jesus portrayed the hard-hearted Pharisees as blind guides, and said, "If the blind lead the blind, both will fall into a pit" (Matthew 15:14). Second Corinthians 4:4 identifies Satan, the god of this world, as the one who "has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God." The apostle John wrote in 1 John 5:19 that "the whole world lies in the power of the evil one." Although believers once followed the Devil, through faith in Jesus Christ, they passed from darkness to light (Ephesians 2:1; 5:8).