HOMILY OF ST GREGORY, POPE, ON John 21:1-14
The lesson from the holy Gospel that has just been read to you, my brethren, urges a question upon the mind, and yet, while urging it, indicates the value of discretion.
For it may be asked why Peter who before his conversion was a fisherman, should after his conversion return again to his fishing? And since the Truth says: “No man putting his hand to the plough, and looking back is fit for the kingdom of God,” why did he take up again what he had once given up?
But, if we look into the matter with some thought, the reason will soon appear; for doubtless, since the business in which he was engaged before his conversion was not a sinful one, he could return to it again after his conversion without committing any fault.
… BUT MATTHEW SAT NO MORE AT THE SEAT OF CUSTOM
Now we know that Peter was a fisherman, and Matthew a tax-gatherer. After his conversion Peter returned to fishing, but Matthew sat no more at the seat of custom: for it is one thing to seek a living by fishing and quite another to amass wealth by profits gained in the gathering of taxes. There are indeed many trades that can hardly, or never, be practised without sin. It is necessary, then, that a man after his conversion should not apply himself again to such occupations as would involve him to sin.
THE SEA REPRESENTS THIS PRESENT WORLD, THE SHORE SIGNIFIES ETERNITY
Again it may be asked why, when the disciples were labouring on the sea, the Lord appeared, after his resurrection, standing on the shore, while before his resurrection he had walked upon the waves of the sea in the sight of his disciples. We shall soon see the reason for this, if we consider the purpose which it served.
For what does the sea represent, if not this present world, surging with the tumult of its ever-shifting fortunes, and with the billows of this corruptible life? What is signified by the solidity of the shore, if not the everlasting peace of eternity? Since, therefore, the disciples were as yet surrounded by the billows of this mortal life, they were struggling on the sea; but since our Redeemer, after his resurrection, had now passed beyond the corruption of the flesh, he was standing on the shore.
– St Gregory, Pope, Homily 24 on the Gospels; from: An Approved English Translation of the Breviarium Romanum, Burns & Oates, London, 1964