John 21:6

(Hom. lxxxvii) He then gives them a sign to know Him by: And He said unto them, Cast the net on the right side of the ship, and ye shall find. They cast therefore, and now they were not able to draw it for the multitude of fishes.

On that previous occasion Jesus stood not, as here, on the shore, when He gave orders for the taking of the fish, but "entered into one of the ships, which was Simon's, and prayed him that he would thrust out a little from the land; and He sat down therein, and taught the crowds. And when He had left speaking, He said unto Simon, Launch out into the deep, and let down your nets for a draught." There also they put the fishes that were caught into the ship, and did not, as here, draw the net to the shore. By these signs, and any others that may be found, on the former occasion the Church was prefigured as it exists in this world, and on the other, as it shall be in the end of the world: the one accordingly took place before, and the other subsequently to the resurrection of the Lord; because there we were signified by Christ as called, and here as raised from the dead. On that occasion the nets are not let down on the right side, that the good alone might not be signified, nor on the left, lest the application should be limited to the bad; but without any reference to either side, He says, "Let down your nets for a draught," that we may understand the good and bad as mingled together: while on this He says, "Cast the net on the right side of the ship," to signify those who stood on the right hand, the good alone.

For a time He speaketh rather after a human manner, as if about to buy somewhat of them. But when they made signs that they had none, He bade them cast their nets to the right; and on casting they obtained a haul.

(Tract. cxxii) Mystically, in the draught of fishes He signified the mystery of the Church, such as it will be at the final resurrection of the dead. And to make this clearer, it is put near the end of the book. The number seven, which is the number of the disciples who were fishing, signifies the end of time; for time is counted by periods of seven days. (Tract. cxxii) The shore is the end of the sea, and therefore signifies the end of the world. The Church is here typified as she will be at the end of the world, just as other draughts of fishes typified her as she is now. Jesus before did not stand on the shore, but went into a ship which was Simon's, and asked him to put out a little from the land. In a former draught the nets are not thrown to the right, or to the left, so that the good or the bad should be typified alone, but indifferently: Let down your nets for a draught, (Luke 5:4) meaning that the good and bad were mixed together. But here it is, Cast the net on the right side of the ship; to signify those who should stand on the right hand, the good. The one our Lord did at the beginning of His ministry, the other after His resurrection, showing therein that the former draught of fishes signified the mixture of bad and good, which composes the Church at present; the latter the good alone, which it will contain in eternity, when the world is ended, and the resurrection of the dead completed. But they who belong to the resurrection of life, i. e. to the right hand, and are caught within the net of the Christian name, shall only appear on the shore, i. e. at the end of the world, after the resurrection: wherefore they were not able to draw the net into the ship, and unload the fishes, as they were before. The Church keeps these of the right hand, after death, in the sleep of peace, as it were in the deep, till the net come to shore. That the first draught was taken in two little ships, the last two hundred cubits from land, a hundred and a hundred, typifies, I think, the two classes of elect, circumcised and uncircumcised.

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.