Charles H. Spurgeon on Psalms 50:10

"For to me (belongs) every beast of the forest, the cattle in hills of a thousand." This last idiomatic phrase may either mean a thousand hills, or hills where the cattle rove by thousands, with probable allusion to the hilly grounds of Bashan beyond Jordan. According to etymology, the noun in the first clause means an animal, and that in the second beasts or brutes in general. But when placed in antithesis, the first denotes a wild beast, and the second domesticated animals or cattle. Both words were necessary to express God's sovereign propriety in the whole animal creation. Thus understood, the verse assigns a reason for the negative assertion in the one before it. Even if God could stand in need of animal oblations, for his own sake, or for their sake, he would not be under the necessity of coming to man for them, since the whole animal creation is his property and perfectly at his disposal. J. A. Alexander.

Verses 11-12. We show our scorn of God's sufficiency, by secret thoughts of meriting from him by any religious act, as though God could be indebted to us, and obliged by us. As though our devotions could bring a blessedness to God more than he essentially hath; when indeed "our goodness extends not to him." Ps 16:2. Our services to God are rather services to ourselves, and bring a happiness to us, not to God. This secret opinion of merit (though disputed among the Papists, yet) is natural to man; and this secret self pleasing, when we have performed any duty, and upon that account expect some fair compensation from God, as having been profitable to him; God intimates this: "The wild beasts of the field are mine. If I were hungry, I would not tell thee; for the world is mine, and the fulness thereof." He implies, that they wronged his infinite fulness, by thinking that he stood in need of their sacrifices and services, and that he was beholden to them for their adoration of him. All merit implies a moral or natural insufficiency in the person of whom we merit, and our doing something for him, which he could not, or at least so well do for himself. It is implied in our murmuring at God's dealing with us as a course of cross providences, wherein men think they have deserved better at the hands of God by their service, than to be cast aside and degraded by him. In our prosperity we are apt to have secret thoughts that our enjoyments were the debts God owes us, rather than gifts freely bestowed upon us. Hence it is that men are more unwilling to part with their righteousness than with their sins, and are apt to challenge salvation as a due, rather than beg it as an act of grace. Stephen Charnock.