What does Psalm 139:21 mean?

David expresses a holy hatred of those who rebel against God. This concept of "hate" has an important context, both in ancient culture and in the Bible. For men like David, this concept of "hate" was mostly an expression of preference and support, not emotion. It would be absurd to suggest that David felt warmth or respect for the enemies of God, and this verse indicates that "loathing" is part of his perspective. Still, what David proclaims here is not the equivalent of the modern English term "hate;" it is part of the biblical pattern of loyalty and preference (Malachi 1:2–3). David also clearly understands that he is capable of sin, as well (Psalm 139:23–24).

The wicked behavior of evil people disgusts David. In that sense, David's attitude mirrors God's attitude. In Psalm 5:5 David wrote, "The boastful shall not stand before your eyes; you hate all evildoers." The Hebrew word translated "loathe" in this verse is from the root quwt, also translated as "sicken" or "abhor." Christians are rightfully sickened by the arrogant sinful actions and language of the wicked.

We must never get so accustomed to the sin around us that we accept it. Even Lot, for all his weakness and compromise, was sickened by the sinful lifestyle he witnessed in Sodom. Second Peter 2:7 describes Lot as being "greatly distressed by the sensual conduct of the wicked." Ephesians 5:11 commands: "Take no part in the unfruitful works of darkness, but instead expose them." We should try to reach sinners for Christ, but some are so saturated with evil that Jude tells us to snatch them "out of the fire; to others show mercy with fear, hating even the garment stained by the flesh" (Jude 1:23).