What does Proverbs 4:17 mean?

Proverbs warns often against following the example of ungodly people. This passage has focused on that warning, that a wise person doesn't have anything to do with evil (Proverbs 4:14–15). The prior verse used exaggeration for effect by saying that "the evil" cannot sleep until they've corrupted someone. This is meant to emphasize the way sin is contagious. When others are sinning, it's easier for people to excuse their own depravity. At the same time, sin consumes a person's life, overpowering all other concerns. Along those same lines, Solomon symbolically compares the effects of sin to dependence on food. When wickedness defines one's life, they cannot get enough of it. There is a constant hunger and thirst for more.

Bread is a common symbol in the Bible, since it's a commonly-known, life-sustaining food. Jesus called Himself "the bread of life" (John 6:35). This was after He referred to manna: bread from heaven that God gave to the Israelites in the wilderness to keep them alive. Jesus explained that He had come down from heaven to give life to the world. He added, "Whoever comes to me shall not hunger, and whoever believes in me shall never thirst" (John 6:35).

Like thirsty souls drinking water at an oasis, the wicked "drink violence." They fall into the same category as those who drink injustice like water and are an abomination to the Lord (Job 15:16). Just as bread and water are assimilated into the human body, so sin and violence become a part of the wicked person. They are what they eat!