1 The miracles performed by our Lord Jesus Christ are indeed divine works, and incite the human mind to rise to the apprehension of God from the things that are seen. But inasmuch as He is not such a substance as may be seen with the eyes, and His miracles in the government of the whole world and the administration of the universal creation are, by their familiar constancy, slightly regarded, so that almost no man deigns to consider the wonderful and stupendous works of God, exhibited in every grain of seed; He has, agreeably to His mercy, reserved to Himself certain works, beyond the usual course and order of nature, which He should perform on fit occasion, that they, by whom His daily works are lightly esteemed, might be struck with astonishment at beholding, not indeed greater, but uncommon works.
For certainly the government of the whole world is a greater miracle than the satisfying of five thousand men with five loaves; and yet no man wonders at the former; but the latter men wonder at, not because it is greater, but because it is rare. For who even now feeds the whole world, but He who creates the cornfield from a few grains? He therefore created as God creates. For, whence He multiplies the produce of the fields from a few grains, from the same source He multiplied in His hands the five loaves.
The power, indeed, was in the hands of Christ; but those five loaves were as seeds, not indeed committed to the earth, but multiplied by Him who made the earth. In this miracle, then, there is that brought near to the senses, whereby the mind should be roused to attention, there is exhibited to the eyes, whereon the understanding should be exercised, that we might admire the invisible God through His visible works; and being raised to faith and purged by faith, we might desire to behold Him even invisibly, whom invisible we came to know by the things that are visible.
Source: Tractates on the Gospel of John (New Advent)