Psalms 109:6 - Coke's Commentary on the Holy Bible

Set thou a wicked man over him— Set a wicked one over him, and let an adversary stand at his right hand. I choose to translate it, says Mudge, by the general word adversary, because it better suits the idea of a judgment or trial. Instead of an advocate's standing at his right hand, as he in the last verse of the psalm intimates God would do for him, he wishes an adversary to stand there, to push the affair against him to the utmost, with a wicked unmerciful man to judge him. Mr. Green, following Dr. Sykes, understands it in a different way, as if these were the words and wishes of David's enemies against him, not of David against his enemies. "Set a wicked man over him, say they, to hear his cause, and let a false accuser, &c." And indeed there seems great probability in this interpretation; as David in the 21st verse, and so on to the end of the psalm, appeals to God from these imprecations of his enemies, and intreats him to bless, although they curse him. In this view it is remarkably striking, that the curses vainly uttered by David's enemies against him should reverberate upon their own heads, and be so singularly verified in the type. See Sykes's Introduction to his Paraphrase on the Hebrews, page 32.