Albert Barnes Commentary Psalms 109:6

"Set thou a wicked man over him; And let an adversary stand at his right hand." — Psalms 109:6 (ASV)

Set you a wicked man over him. This begins the imprecatory part of the psalm, extending to Psalm 109:20. The first thing the psalmist asks is that his foe might be subjected to the evil of having a man placed over him like himself: a man regardless of justice, truth, and right, who would respect character and propriety no more than he himself had done. It is, in fact, a prayer that he might be punished “in the line of his offenses.”

It cannot be wrong that a man should be treated as he treats others; and it cannot be inherently wrong to desire that a man be treated according to his character and deserts. For this is the object of all law, and this is what all magistrates and legislators are striving to secure.

And let Satan stand at his right hand. This means as his counselor and adviser. This language would properly apply to one who had been a counselor or adviser to a king in the administration of the government. The prayer is that he might know what it was to have such a person as his counselor and adviser.

The language used makes it seem likely that David here refers particularly to someone who had occupied this position in relation to himself and who had betrayed his trust. This person had given him crafty and malignant counsel, had led him into poor decisions, and had used his position to promote his own interests at his master’s expense. David had such counselors, as anyone in authority may have. The prayer, then, would be that such a man might be punished in his own line—that he might know what it is to have a bad and wicked adviser.

The word translated “Satan” – שׂטן śâṭân – is in the margin translated “adversary.” In the Septuagint it is διάβολος diabolos; in the Vulgate, “diabolus.” (See the notes at Job 1:6 for its meaning.)

The prayer here seems not to be that the devil, or Satan, might stand near him as his counselor. Instead, it is that a man—a real adversary, an accuser, one with a malignant heart, one who would use his position to accomplish his own purposes and betray his master’s interests—might give him counsel, as seems to have happened in David’s case.