John Calvin Commentary Isaiah 40:16

"And Lebanon is not sufficient to burn, nor the beasts thereof sufficient for a burnt-offering." — Isaiah 40:16 (ASV)

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 extensively on this power of God, so that people, being convinced of it, may disregard creatures and all their power.

Yet the Prophet appears to speak explicitly 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 adequately prepared to worship correctly, even if you were to amass all the beasts and all the wood that are on Lebanon?”

Therefore, some infer that no one can merit God's favor by sacrifices. This, indeed, is true; but we should, as has already been said, consider the Prophet's purpose, who, in order to encourage the Jews to cherish stronger confidence, shows that in comparison with God, all things are nothing.