The Calvinist doctrine of God is sometimes caricatured as naked voluntarism, the triumph of the will: God is sheer power and does what he likes–as if to say Calvin comes down on one side of the Euthyphro dilemma, the side that says the pious is pious because it is loved by God, his loving it makes it pious.
This is, of course, wrong. God’s judgments are unsearchable, and his ways past finding out, but this does not mean that God does not will and act in accordance with his supremely good, wise, and perfect nature. Calvin says as much when commenting on Mary’s song in the first chapter of Luke’s Gospel. On the phrase, “He hath cast down the nobles,” Calvin writes:
Let us understand, that she does not ascribe to God a despotic power,—as if men were tossed and thrown up and down like balls by a tyrannical authority,—but a just government, founded on the best reasons, though they frequently escape our notice.
When men are removed from high position, it is not because of arbitrariness or the whim of God, but rather to their own sin:
God does not delight in changes, or elevate in mockery to a lofty station, those whom he has determined immediately to throw down. It is rather the depravity of men that overturns the state of things, because nobody acknowledges that the disposal of every one is placed in His will and power.
Incidentally, this truth about fallen human nature explains, for Calvin, why we should expect to see continual upheavals and changes of rule in the civil sphere: the overweening pride of men in power will lead regularly to their downfall:
We see, indeed, how the princes of the world grow extravagantly insolent, indulge in luxury, swell with pride, and are intoxicated with the sweets of prosperity. If the Lord cannot tolerate such ingratitude, we need not be surprised.
The usual consequence is, that those whom God has raised to a high estate do not occupy it long. Again, the dazzling luster of kings and princes so overpowers the multitude, that there are few who consider that there is a God above. But if princes brought a scepter with them from the womb, and if the stability of their thrones were perpetual, all acknowledgment of God and of his providence would immediately disappear. When the Lord raises mean persons to exalted rank, he triumphs over the pride of the world, and at the same time encourages simplicity and modesty in his own people.
For Calvin, the casting down of princes is a reminder of God’s existence and providential rule.