John Calvin Commentary Psalms 9:8

"And he will judge the world in righteousness, He will minister judgment to the peoples in uprightness." — Psalms 9:8 (ASV)

And he shall judge the world in righteousness. As David has just testified, the power of God is not inactive, as if he dwells in heaven only indulging himself in pleasures. Instead, it is a constantly operating power that he exercises in preserving his authority and governing the world in righteousness and equity. So, in this verse, David adds the application of this doctrine: that the power of God is not confined to heaven but manifests itself in helping humanity.

The true doctrine on this subject is not to imagine, like Epicurus, that God is a being entirely devoted to ease and pleasures, who, satisfied with himself alone, has no concern whatever for humankind. Instead, it is to place him on the throne of power and equity, so that we may be fully convinced that although he does not immediately help those who are unjustly oppressed, yet there is not a moment in which he ceases to take a deep interest in them.

And when he seems for a time to take no notice, we should most assuredly conclude not that he deserts his office, but that he wishes by this to test the patience of his people. Therefore, we should wait for the outcome patiently and with peace of mind.

The demonstrative pronoun He, in my opinion, carries great weight. Its meaning is as if David had said: No one can deprive God of his office as Judge of the world, nor prevent him from extending his judgments to all nations. From this it follows that he will all the more be the judge of his own people.

David declares these judgments to be righteous, to encourage us, when we are unjustly and cruelly troubled, to ask for assistance from God, confidently expecting to receive it. For since he judges the nations in righteousness, he will not allow injustice and oppression always to reign with impunity in the world, nor deny his aid to the innocent.