John Calvin Commentary Psalms 28:9

"Save thy people, and bless thine inheritance: Be their shepherd also, and bear them up for ever." — Psalms 28:9 (ASV)

In this verse he shows that his concern was not so much for his own welfare as for the welfare of the whole Church, and that he neither lived nor reigned for himself, but for the common good of the people. He well knew that he was appointed king for no other purpose.

In this he declares himself to be a type of the Son of God; of whom, when Zechariah (Zechariah 9:9) predicts that He would come having salvation, there is no doubt that he promises nothing to Him apart from His members, but that the effects of this salvation would diffuse themselves throughout His whole body.

By this example, accordingly, he prescribes a rule to earthly kings: that, devoting themselves to the public good, they should desire to be preserved only for the sake of their people. How very far otherwise it is, it is needless to say. Blinded by pride and presumption, they despise the rest of the world, just as if their pomp and dignity raised them altogether above the common state of humanity.

Nor is it surprising that humankind is so haughtily and contemptuously trampled underfoot by kings, since most people cast off and disdain to bear the cross of Christ. Let us therefore remember that David is like a mirror, in which God sets before us the continual course of His grace.

We must be careful, however, that the obedience of our faith corresponds to His fatherly love, so that He may acknowledge us as His people and inheritance. The Scriptures often designate David as a shepherd; but David himself assigns that office to God, thus confessing that he is altogether unfit for it, except insofar as he is God’s minister.