Albert Barnes Commentary Psalms 9:19

"Arise, O Jehovah; let not man prevail: Let the nations be judged in thy sight." — Psalms 9:19 (ASV)

Arise, O Lord - See the notes at Psalms 3:7.

Let not man prevail - Against you and your cause. The psalmist regarded the war waged against him as waged against God, and he therefore calls upon Him to intervene and vindicate His own cause. The word rendered “prevail” is ‘be strong’; that is, let man not seem to be stronger than you are, or let him not succeed in his efforts in opposing your cause.

Let the heathen be judged in your sight - The nations to whom the writer had referred in the psalm, who were arrayed against him and against God. He desired that a just judgment would be passed on them, and that God would vindicate the righteous and save them from the power of those who oppressed and wronged them.