What does Proverbs 14:17 mean?

The danger of our temper is that it operates on instinct, not on careful thought. Flying off the handle at the slightest provocation, or for no reason at all, or without exerting self-control shows how foolish a person is (2 Peter 2:12). People controlled by their temper may say things they will later regret or do things that land them in trouble (Proverbs 14:3, 14).

Scripture warns believers to put aside anger (Ephesians 4:31). James 1:19–20 teaches: "Know this, my beloved brothers: let every person be quick to hear, slow to speak, slow to anger; for the anger of man does not produce the righteousness of God." Fortunately, the Lord can transform an angry heart into a loving heart. He transformed the apostle John from a "son of thunder" into the apostle who appealed for brotherly love (Mark 3:17; Luke 9:54; 1 John 3:11).

A crafty person, who schemes to inflict harm on others is the person with "evil devices." Such a person can expect to be despised by others, to say nothing of those they harm. This pattern is seen in the workplace, the neighborhood, and even within the family. Those who manipulate or plot to take advantage of other people are seldom liked, and almost never respected.