John Calvin Commentary Psalms 50:3

"Our God cometh, and doth not keep silence: A fire devoureth before him, And it is very tempestuous round about him." — Psalms 50:3 (ASV)

Our God shall come, and shall not keep silence. He repeats that God would come in order to confirm his doctrine and more effectively arouse them. He would come and would not always keep silence, so that they would not be encouraged to presume upon his patience.

Two reasons may be given why the prophet calls God our God. He may be considered as setting himself, and the comparatively small number of those who truly fear the Lord, in opposition to the hypocrites whom he abhors, claiming God to be his God and not theirs, as they were inclined to boast. Or rather, he speaks as one of the people and declares that the God who was coming to avenge the corruptions of his worship was the same God whom all the children of Abraham professed to serve. He who will come, as if he had said, is our God, the same in whom we glory, who established his covenant with Abraham and gave us his Law by the hand of Moses.

He adds that God would come with fire and tempest to awaken a wholesome fear in the complacent hearts of the Jews, so that they might learn to tremble at the judgments of God, which they had until then regarded with indifference and despised. This alludes to the awe-inspiring manifestation God made of himself from Sinai (Exodus 19:16). On that occasion, the air resounded with thunders and the noise of trumpets, the heavens were illuminated with lightnings, and the mountain was in flames, as it was God's design to secure reverential submission to the Law which he announced.

And it is implied here that God would make a similarly terrifying display of his power in coming to avenge the gross abuses of his holy religion.