John Calvin Commentary Psalms 122:5

"For there are set thrones for judgment, The thrones of the house of David." — Psalms 122:5 (ASV)

For there were set thrones for judgment. He means that the throne of the kingdom was fixed or established in Jerusalem, or that it had its permanent seat there. Among that people, some system of judgments had always existed; however, these had previously been in an unsettled state and frequently changed. But God at last ordained, in the person of David, a new government that would continue in an unbroken succession, for it was His will that the descendants of David should succeed their father in this royal dignity from generation to generation until the coming of Christ.

A little earlier, the Prophet spoke of the Temple and the priesthood; and now he affirms that this kingdom, which God had established, will be firm and stable, in order to distinguish it from all the other kingdoms of the world, which are not only temporary but also frail and subject to a variety of changes.

This permanence of the kingdom has been expressly confirmed by other Prophets in various parts of their writings, and not without reason. For the purpose was to teach the faithful that God would be the guardian of their well-being only if they remained under the protection and defense of David, and that, therefore, if they desired to continue in safety and to prosper, they should not create new kings for themselves according to their own pleasure, but should live quietly under the kind of government that God had established among them.

The repetition of the word throne is emphatic. There, says the Psalmist, the throne of judgment and equity is established. Then he adds, the throne of the house of David; for it was God’s will that the right and prerogative of reigning should continue in David’s posterity, until the true permanence of this kingdom would be manifested in the person of Christ.