4 But some one will reply, And why did he not find them, when the Lord had promised, saying, “Seek first the kingdom and righteousness of God, and all these things shall be added unto you”? Precisely also in this very way did the Lord fulfill His promise. For who else placed there the fishes that were to be caught, but He, who, we are bound to believe, threw them into the penury that compelled them to go a fishing, for no other reason than that He wished to show them the miracle He had prepared, that so He might both feed the preachers of His gospel, and at the same time enhance that gospel itself, by the great mystery which He was about to impress on their minds by the number of the fishes? And on this subject we also ought now to be telling you what He Himself has set before us.
Source: Tractates on the Gospel of John (New Advent)