John Calvin Commentary Psalms 99:8

"Thou answeredst them, O Jehovah our God: Thou wast a God that forgavest them, Though thou tookest vengeance of their doings." — Psalms 99:8 (ASV)

O Jehovah our God. The prophet here reminds them that God had heard their prayers because his grace and their piety harmonized. Consequently, encouraged by their exemplary success in prayer, their posterity ought to call upon God, not merely pronouncing his name with their lips, but keeping his covenant with all their heart. He further reminds us that if God does not display his glory so bountifully and so profusely in every age, the fault lies with people themselves, whose posterity have either utterly forsaken or greatly declined from the faith of their ancestors. It is not surprising that God should withdraw his hand, or at least not extend it in any remarkable way, when he sees piety growing cold on the earth.

O God, you have been propitious to them. From these words it is quite clear that what the Psalmist had previously said concerning Moses, Aaron, and Samuel refers to the whole people; for surely they did not officiate as priests merely for their own benefit, but for the common benefit of all the Israelites.

Therefore, the transition the psalmist makes from these three individuals to the rest of the people is more natural. For I do not restrict this term to these three persons, nor do I interpret it as referring exclusively to them; rather, I believe that the state of the whole Church is indicated: namely, that while God, at the prayers of the priests, was propitious to the Jews, he, at the same time, sharply punished them for their sins.

On the one hand, the prophet magnifies the grace of God, in that he had treated the people so kindly and had so mercifully forgiven their iniquity. On the other hand, he specifies those terrible examples of punishment by which God punished them for their ingratitude, so that their descendants might learn to submit dutifully to him. For it must not be forgotten that the more graciously God deals with us, the less easily he will tolerate our treating his generosity with scorn.

At the end of the psalm, he repeats the same sentence that we found in verse five, only substituting his holy mountain for his footstool; and as, for the sake of brevity, he had previously said somewhat obscurely, קדוש הוא, kadosh hu, he is holy, he now says more plainly, Jehovah our God is holy. His intention is to show that God is not to be worshipped by the Israelites haphazardly (as the religion of pagans depended on imagination alone), but that his worship is founded upon the assurance of faith.