15 What then, brethren? Why have I said these things? Shut the ears of your hearts against the wiles of the enemy. Understand that God made all things, and arranged them in their orders. Why, then, do we suffer many evils from a creature that God made? Because we have offended God? Do angels suffer these things? Perhaps we, too, in that life of theirs, would have no such thing to fear. For your punishment, accuse your sin, not the Judge. For, on account of our pride, God appointed that tiny and contemptible creature to torment us; so that, since man has become proud and has boasted himself against God, and, though mortal, has oppressed mortals, and, though man, has not acknowledged his fellowman—since he has lifted himself up, he may be brought low by gnats.
Why are you inflated with human pride? Some one has censured you, and you are swollen with rage. Drive off the gnats, that you may sleep: understand who you are. For, that you may know, brethren, it was for the taming of our pride these things were created to be troublesome to us, God could have humbled Pharaoh's proud people by bears, by lions, by serpents; He sent flies and frogs upon them, that their pride might be subdued by the meanest creatures.
Source: Tractates on the Gospel of John (New Advent)