Albert Barnes Commentary Psalms 119:21

"Thou hast rebuked the proud that are cursed, That do wander from thy commandments." — Psalms 119:21 (ASV)

Thou hast rebuked the proud - . The meaning is that God had done this not by word but by deed. The proud were everywhere rebuked by God, alike in His law and in His providence.

The connection seems to be this: the psalmist is meditating on the benefit or advantage of keeping the law of God; of a humble, pious life. His mind naturally turns to what would be the opposite of this—or to this in contrast with an opposite course of life. He says, therefore, that God had in every way and at all times manifested His displeasure against that class of people.

Such a course, therefore, must be attended with misery; but the course which he proposed to pursue must be attended with happiness.

That are cursed - The accursed; those who are regarded and treated by God as accursed, or as objects of His disapproval.

Which do err from thy commandments - Who depart from Your law. The sense is, “I propose and intend to keep Your law. As a motive to this, I look at the consequences which must follow from disobeying it. I see it everywhere in the divine treatment of those who do disregard that law. They are subject to the displeasure—the solemn rebuke—of God. So all must be who disregard His law; and it is my purpose not to be found among their number.”