Here is, 1. The character of wicked people; he means those that are openly and grossly wicked: They forsake thy law. Every sin is a transgression of the law, but a course and way of wilful and avowed sin is downright forsaking it and throwing it off. 2. The impression which the wickedness of the wicked made upon David; it frightened him, it put him into an amazement. He trembled to think of the dishonour thereby done to God, the gratification thereby given to Satan, and the mischiefs thereby done to the souls of men. He dreaded the consequences of it both to the sinners themselves (and cried out, O gather not my soul with sinners! let my enemy be as the wicked) and to the interests of God's kingdom among men, which he was afraid would be thereby sunk and ruined. He does not say, "Horror has taken hold on me because of their cruel designs against me," but "because of the contempt they put on God and his law." Sin is a monstrous horrible thing in the eyes of all that are sanctified, Jer 5:30; Jer 23:14; Hos 6:10; Jer 2:12.