Can the Psalms both point to Christ for fulfillment and be more broadly pedagogical at the same time? Calvin thought so. An interesting test-case is provided by his comments on Psalm 72:1 (“O God! give thy judgments to the king, and thy righteousness to the king’s son”).
This verse finds its fulfillment through special grace in the “sacred kingdom” of Christ and not in Old Testament Israel or any other earthly kingdom; yet Calvin thinks that there is still something to be learned here vis-a-vis the government and maintenance of earthly kingdoms. For Calvin, kings need wisdom, and wisdom only comes from God; ergo...
His exegetical practice here presupposes that the typological aspect of the Psalms, while absolutely crucial, does not exhaust what one is able to say about them, and so Calvin reflects on the generalities of civil, earthly government in addition to the particularities of the messianic kingdom.
While David, to whom the promise had been made, at his death affectionately recommended to God his son, who was to succeed him in his kingdom, he doubtless endited to the Church a common form of prayer, that the faithful, convinced of the impossibility of being prosperous and happy, except under one head, should show all respect, and yield all obedience to this legitimate order of things, and also that from this typical kingdom they might be conducted to Christ. In short, this is a prayer that God would furnish the king whom he had chosen with the spirit of uprightness and wisdom. By the terms righteousness and judgment, the Psalmist means a due and well-regulated administration of government, which he opposes to the tyrannical and unbridled license of heathen kings, who, despising God, rule according to the dictates of their own will; and thus the holy king of Israel, who was anointed to his office by divine appointment, is distinguished from other earthly kings. From the words we learn by the way, that no government in the world can be rightly managed but under the conduct of God, and by the guidance of the Holy Spirit. If kings possessed in themselves resources sufficiently ample, it would have been to no purpose for David to have sought by prayer from another, that with which they were of themselves already provided. But in requesting that the righteousness and judgment of God may be given to kings, he reminds them that none are fit for occupying that exalted station, except in so far as they are formed for it by the hand of God. Accordingly, in the Proverbs of Solomon, (Proverbs 8:15,) Wisdom proclaims that kings reign by her. Nor is this to be wondered at, when we consider that civil government is so excellent an institution, that God would have us to acknowledge him as its author, and claims to himself the whole praise of it. But it is proper for us to descend from the general to the particular; for since it is the peculiar work of God to set up and to maintain a rightful government in the world, it was much more necessary for him to communicate the special grace of his Spirit for the maintenance and preservation of that sacred kingdom which he had chosen in preference to all others. By the king’s son David no doubt means his successors. At the same time, he has an eye to this promise:
“Of the fruit of thy body will I set upon thy throne,”
But no such stability as is indicated in that passage is to be found in the successors of David, till we come to Christ. We know that after the death of Solomon, the dignity of the kingdom decayed, and from that time its wealth became impaired, until, by the carrying of the people into captivity, and the ignominious death inflicted upon their king, the kingdom was involved in total ruin. And even after their return from Babylon, their restoration was not such as to inspire them with any great hope, until at length Christ sprung forth from the withered stock of Jesse. He therefore holds the first rank among the children of David.