John Calvin Commentary Psalms 150:1

"Praise ye Jehovah. Praise God in his sanctuary: Praise him in the firmament of his power." — Psalms 150:1 (ASV)

Praise God in his sanctuary. This psalm generally commends the spiritual worship of God, which consists in sacrifices of praise. By the sanctuary, there is little doubt that heaven is meant here, as is often the case elsewhere. The second clause is exegetical, for the same thing is repeated.

But for sanctuary, we read רקיע, rekia, that is, the expanse of heaven, to which is added the epithet of power, because there we have proof of the matchless power of God, so that we cannot look to the heavens without being lost in admiration. As for the interpretation which some give—Praise God, you angels who inhabit the heavens, and you men who dwell under the firmament—it is forced and unnatural, because the Psalmist, in order to awaken men who grow languid in God’s praises, tells them to lift their eyes towards the heavenly sanctuary.

So that the majesty of God may be duly reverenced, the Psalmist represents him as presiding on his throne in the heavens. He also enlarges upon the same truth in the second verse, celebrating his power and his greatness, which he had brought to our attention in the heavens, which are a mirror in which they may be seen.

If, then, we wish for our minds to be kindled to engage in this religious service, let us meditate upon his power and greatness, which will speedily dispel all such insensibility. Though our minds can never fully grasp this immensity, the mere taste of it will deeply affect us. And God will not reject such praises as we offer according to our capacity.