Unless we have tangible proof of our weaknesses, we immediately get inflated ideas of our own abilities, and readily imagine that they can prevail over every conceivable difficulty. So it is that we develop an empty, foolish confidence in the flesh, which then produces a supercilious attitude toward God, as if our own resources were sufficient without his grace. God has no better way of humbling such arrogance than by showing us by hard experience how weak and feeble we are. So he brings disgrace, poverty or sickness upon us, or loss of kin or other calamities which, try as we may, at once overwhelm us, because we are not strong enough to bear them. Hence, being humbled, we learn to plead for his power, which alone allows us to stand firm and to hold up under the weight of such burdens.
Calvin, John, and Robert White. "The Christian Life." Institutes of the Christian Religion. Edinburgh: Banner of Truth Trust, 2014. 801.