to bring rain on a barren land, on a desert where no man lives,
Hitherto God had put such questions to Job as were proper to convince him of his ignorance and short-sightedness. Now he comes, in the same manner, to show his impotency and weakness. As it is but little that he knows, and therefore he ought not to arraign the divine counsels, so it is but little that he can do, and therefore he ought not to oppose the proceedings of Providence.
Commenting on Job 38:25-41
Hath the rain a father?.... None but God; hence the Heathens themselves call God (y), and (z); see Jer 14:22; he that is our Father in heaven is the Father of rain, and him only; whatever secondary causes there be, God only is the efficient cause, parent, and producer of it: so the Gospel is not of men but of God, is a gift of...
Since rain fails also on places uninhabited by man, it cannot be that man guides its course. Such rain, though man cannot explain the reason for it, is not lost. God has some wise design in it.