God Owns Everything.

"There is no neutral ground in the universe; every square inch, every split second, is claimed by God and counter-claimed by Satan." - C.S. Lewis

The earth is Jehovah’s. We will find in many other places the children of Abraham compared with all the rest of mankind, that the free goodness of God, in selecting them from all other nations, and in embracing them with his favor, may shine forth the more conspicuously. The object of the beginning of the psalm is to show that the Jews had nothing of themselves which could entitle them to approach nearer or more familiarly to God than the Gentiles. As God by his providence preserves the world, the power of his government is alike extended to all, so that he ought to be worshipped by all, even as he also shows to all men, without exception, the fatherly care he has about them. But since he preferred the Jews to all other nations, it was indispensably necessary that there should be some sacred bond of connection between him and them, which might distinguish them from the heathen nations. By this argument David invites and exhorts them to holiness. He tells them that it was reasonable that those whom God had adopted as his children, should bear certain marks peculiar to themselves, and not be altogether like strangers. Not that he incites them to endeavor to prejudice God against others, in order to gain his exclusive favor; but he teaches them, from the end or design of their election, that they shall then have secured to them the firm and peaceful possession of the honor which God had conferred upon them above other nations, when they devote themselves to an upright and holy life. 540 In vain would they have been collected together into a distinct body, as the peculiar people of God, if they did not apply themselves to the cultivation of holiness. In short, the Psalmist pronounces God to be the King of the whole world, to let all men know that, even by the law of nature, they are bound to serve him. And by declaring that he made a covenant of salvation with a small portion of mankind, and by the erection of the tabernacle, gave the children of Abraham the symbol of his presence, thereby to assure them of his dwelling in the midst of them, he teaches them that they must endeavor to have purity of heart and of hands, if they would be accounted the members of his sacred family.

With respect to the word fullness, I admit that under it all the riches with which the earth is adorned are comprehended, as is proved by the authority of Paul; but I have no doubt that the Psalmist intends by the expression men themselves, who are the most illustrious ornament and glory of the earth. If they should fail, the earth would exhibit a scene of desolation and solitude, not less hideous than if God should despoil it of all its other riches. To what purpose are there produced so many kinds of fruit, and in so great abundance, and why are there so many pleasant and delightful countries, if it is not for the use and comfort of men? 541 Accordingly, David explains, in the following clause, that it is principally of men that he speaks. It is his usual manner to repeat the same thing twice, and here the fullness of the earth, and the inhabitants of the world, have the same meaning. I do not, however, deny that the riches with which the earth abounds for the use of men, are comprehended under these expressions. Paul, therefore, (1 Corinthians 10:26) when discoursing concerning meats, justly quotes this passage in support of his argument, maintaining that no kind of food is unclean, because, “the earth is the Lord’s, and the fullness thereof.” - John Calvin