John Calvin on Isaiah 40:16

16. And Lebanon would not be sufficient. That is, “If we must sacrifice to God according to what he deserves, neither the whole of Lebanon, nor the beasts that graze upon it, would be sufficient for a sacrifice.” By various forms of expression he dwells largely on this power of God, that men, being’ convinced of it, may care nothing about creatures and all their might. Yet the Prophet appears to speak expressly of the worship of God, in order to lead readers to cherish deeper reverence for him; as if he had said, “Will you dare to measure by your own judgment the power of God, whom you will not be prepared, for worshipping aright, even though you should amass all the beasts and all the wood that are on Lebanon?” Hence some infer that no man can entitle himself to the favor of God by sacrifices. This, indeed, is true; but we ought, as has been already said, to consider the design of the Prophet, who, for the purpose of encouraging the Jews to cherish stronger confidence, shews that in comparison of God all things are nothing.