John Gill Commentary Psalms 89:42

"Thou hast exalted the right hand of his adversaries; Thou hast made all his enemies to rejoice." — Psalms 89:42 (ASV)

You have set up the right hand of his adversaries
Suffered them to become powerful, and to prevail against him; as the wicked Jews, and Satan, and his principalities and powers, at the time of Christ's apprehension, crucifixion, and death; for then were their hour, and the power of darkness, (Luke 22:53), death also has dominion over him, and held him under the power of it for awhile: the enemies of his interest, Rome Pagan, and Rome Papal, have, in their turns, had their right hands set up, and have had power, and prevailed over it; and the latter will again, at the slaying of the witnesses.

All which, though it seems contrary to (Psalms 89:21–25Psalms 89:27), yet is not; for Satan, though he bruised Christ's heel, yet Christ bruised his head, destroyed his works, and him himself, and that by dying; and spoiled his principalities and powers; and death could not hold him long, nor has it now any dominion over him, and is abolished by him; and antichrist, and all the antichristian powers, will be destroyed by him before long.

you have made all his enemies to rejoice;
as they did when they had got him on the cross; and especially when he was laid in the grave, (Psalms 22:7Psalms 22:8) (41:8), and as the antichristian party will when his witnesses are slain, (Revelation 11:10), but as the joy of the former was short lived, and was soon turned into sorrow, so will be that of the latter.