John Calvin Commentary Psalms 103:19

"Jehovah hath established his throne in the heavens; And his kingdom ruleth over all." — Psalms 103:19 (ASV)

Jehovah hath established his throne in the heavens. David, having recounted the benefits by which God places each of us in particular, and also the whole Church, under obligation to Him, now, in general, praises highly His infinite glory. The main point is that whenever God is mentioned, people should learn to elevate their thoughts above the whole world, because His majesty transcends the heavens. They should further learn not to measure His power by human standards, since it holds all kingdoms and dominions under its control.

So that no one thinks that only earthly creatures are placed in subjection to God here, the Psalmist primarily addresses the angels. In calling on them to join in praising God, he teaches both himself and all the godly that there is no better or more desirable exercise than to praise God, since there is no more excellent service in which even the angels engage.

The angels are undoubtedly too willing and prompt in performing this duty to need encouragement from us. How then, one might ask, can we, whose sluggishness is so great, take it upon ourselves to exhort them?

But although these exalted beings run swiftly before us, and we struggle to follow, lagging behind them, yet David urges them to sing God’s praises for our benefit, so that by their example he may awaken us from our drowsiness. His purpose, as I have mentioned before, should be noted: by addressing his words to the angels, he aims to teach us that the highest goal they set for themselves is to promote God's glory.

Accordingly, while in one sentence he clothes them with strength, in the one immediately following, he describes them as hanging on God’s word, waiting for His commands—Ye who do his commandment. However great the power, as if he had said, with which you are endowed, you consider nothing more honorable than to obey God. And it is not only stated that they carry out God’s commands, but to express more clearly the promptness of their obedience, it is affirmed that they are always ready to do whatever He commands them.