John Calvin Commentary Psalms 72:5

"They shall fear thee while the sun endureth, And so long as the moon, throughout all generations." — Psalms 72:5 (ASV)

They shall fear thee with the sun If this is read as an apostrophe, or a change of person, it can be properly and without distorting the meaning understood as referring to the king. This implies that the attributes that chiefly earn a sovereign reverence from his subjects are: his impartially securing for every person the possession of their own rights; his manifesting a spirit of humanity always ready to help the poor and miserable; and his demonstrating a spirit determined rigorously to subdue the audacity of the wicked.

But it will be more appropriate, without changing the person, to explain it as referring to God Himself. The preservation of mutual equity among people is an inestimable blessing, but the service of God is well worthy of being preferred even to this. David, therefore, very properly commends to us the blessed fruits of a holy and righteous government by telling us that it will bring in its wake true religion and the fear of God.

And Paul, when instructing us in 1 Timothy 2:2 to pray for kings, expressly mentions what we should aim for in our prayers, which is, that we may lead a quiet and peaceable life in all godliness and honesty. Since there is considerable danger that if civil government were overthrown, religion would be destroyed and the worship of God annihilated, David implores God to have regard for His own name and glory in preserving the king.

By this argument he simultaneously reminds kings of their duty and stirs up the people to prayer, for we cannot be better occupied than in directing all our desires and prayers to the advancement of the service and honor of God. When we consider Christ, this is far more truly applicable to Him, as true religion is established in His kingdom and nowhere else.

And certainly David, in describing the worship or service of God as continuing to the end of the world, implies in passing that his thoughts ascend to that everlasting kingdom which God had promised: They shall fear thee with the sun; and generation of generations shall fear thee in the presence of the moon.