John Calvin on Deuteronomy 28:38-42

38. Thou shalt carry much seed out into the field. He again makes mention of the scarcity of wine, of wheat, and all sorts of corn; but He assigns different causes for it. He proclaims that the harvest shall be scanty, notwithstanding an abundant sowing, because the locust shall consume the seed; that the vintage shall be poor, nay, almost nothing, because the worms shall devour the bunches; that the oil produced should be little, because the olives should wither on the trees and fall of themselves. Thus He admonishes them that He has at hand innumerable ministers (satellites) wherewith to destroy by famine the transgressors of His Law. Thus, whenever we see beetles, and locusts, and other insects attacking the fruits, we should remember that God, as it were, puts forth His arm to take away the food which He had given: thus Joel reminds us, that when the locust eats that which the palmer-worm hath left, and another insect that which the locust hath left, the curse of God is sufficiently conspicuous. “Que la main de Dieu est toute evidente;” that God’s hand is quite evident. — Fr. (Joel 1:4.) Philosophers discover the reason why more of these little creatures are generated in one year than another; but we must remember the teaching of Moses, that they never trouble us except by God’s command. For if we were submissive to God, as we ought to be, such a prodigy would never happen as that vile and filthy insects should devour the fruits of the earth which He Himself has provided for the sustenance of His children.