From: John 21:1-19
The Miraculous Draught of Fish
 After this Jesus revealed Himself again to the disciples by the Sea of Tiberias; and He revealed Himself in this way.  Simon Peter, Thomas called the Twin, Nathaniel of Cana in Galilee, the sons of Zebedee, and two others of His disciples were together.  Simon Peter said to them, "I am going fishing." They said to him, "We will go with you." They went out and got into the boat; but that night they caught nothing.
 Just as day was breaking, Jesus stood on the beach; yet the disciples did not know that it was Jesus.  Jesus said to them, "Children, have you any fish?" They answered Him, "No."  He said to them, "Cast the net on the right side of the boat, and you will find some." So they cast it, and now they were not able to haul it in, for the quantity of fish.  That disciple whom Jesus loved said to Peter, "It is the Lord!" When Simon Peter heard that it was the Lord, he put on his clothes, for he was stripped for work, and sprang into the sea.  But the other disciples came in the boat, dragging the net full of fish, for they were not far from the land, but about a hundred yards off.
 When they got out on land, they saw a charcoal fire there, with fish lying on it, and bread.  Jesus said to them, "Bring some fish that you have just caught."  So Simon Peter went aboard and hauled the net ashore, full of large fish, a hundred and fifty-three of them; and although there were so many, the net was not torn.  Jesus said to them, "Come and have breakfast." Now none of the disciples dared ask Him, "Who are you?" They knew it was the Lord.  Jesus came and took the bread and gave it to them, and so with the fish.  This was now the third time that Jesus was revealed to the disciples after He was raised from the dead.
 When they had finished breakfast, Jesus said to Simon Peter, "Simon, son of John, do you love Me more than these?" He said to Him, "Yes, Lord; you know that I love You." He said to him, "Feed My lambs."  A second time He said to him, "Simon, son of John, do you love Me?" He said to Him, "Yes, Lord, you know I love You." He said to him, "Tend My sheep."  He said to him the third time, "Simon, son of John, do you love Me?" Peter was grieved because He said to him the third time, "Do you love Me?" And he said to Him, "Lord, You know everything; You know that I love You." Jesus said to him, "Feed My sheep.  Truly, truly I say to you, when you were young, you girded yourself and walked where you would; but when you are old, you will stretch out your hands, and another will gird you and carry you where you do not wish to go."  (This He said to show by what death he was to glorify God.) And after this He said to him, "Follow Me."
1-3. There are some very significant things in this account: we find the disciples "by the Sea of Tiberias", which means they have done what the risen Christ had told them to do (cf. Matthew 28:7); they are together, which shows that there is a close fraternity among them; Peter takes the initiative, which in a way shows his authority; and they have gone back to their old jobs as fishermen, probably waiting for our Lord to give them new instructions.
This episode is reminiscent of the first miraculous draught of fish (cf. Luke 5:111), where our Lord promised Peter He would make him a fisher of men; now He is going to confirm his mission as visible head of the Church.
4-8. The risen Jesus goes in search of His disciples, to encourage them and tell them more about the great mission He has entrusted to them. This account describes a very moving scene, our Lord together with His own: "He passes by, close to His Apostles, close to those souls who have given themselves to Him, and they do not realize He is there. How often Christ is not only near us, but in us; yet we still live in such a human way!... They, the disciples, recall what they have heard so often from their Master's lips: fisher of men, apostles. And they realize that all things are possible, because it is He who is directing their fishing.
"Whereupon 'the disciple whom Jesus loved said to Peter, It is the Lord!' Love, love is farsighted. Love is the first to appreciate kindness. The adolescent Apostle, who felt a deep and firm affection for Jesus, because he loved Christ with all the purity and tenderness of a heart that had never been corrupted, exclaimed: 'It is the Lord!'"
"'When Simon Peter heard that it was the Lord, he put on his clothes and sprang into the sea.' Peter personifies faith. Full of marvelous daring, he leaps into the sea. With a love like John's and a faith like Peter's, what is there that can stop us?" (St. J. Escriva, "Friends of God", 265-266).
9-14. We can sense here the deep impression this appearance of the risen Jesus must have made on the Apostles, and how sweet a memory St. John kept of it. After His resurrection Jesus showed the same tenderness as characterized His public ministry. He makes use of natural things -- the fire, the fish, et cetera -- to show that He really is there, and He maintains the familiar tone typical of when He lived with the disciples.
The Fathers and Doctors of the Church have often dwelt on the mystical meaning of this episode: the boat is the Church, whose unity is symbolized by the net which is not torn; the sea is the world, Peter in the boat stands for supreme authority of the Church, and the number of fish signifies the number of the elect (cf. St. Thomas Aquinas, "Commentary on St. John, in loc.").
15-17. Jesus Christ had promised Peter that he would be the primate of the Church (cf. Matthew 16:16-19 and note on the same). Despite his three denials during our Lord's passion, Christ now confers on him the primacy He promised.
"Jesus questions Peter, three times, as if to give him a triple chance to atone for his triple denial. Peter has learned his lesson from the bitter experience of his wretchedness. Aware of his weakness, he is deeply convinced that rash claims are pointless. Instead he puts everything in Christ's hands. 'Lord, You know well that I love You" (St. J. Escriva, "Friends of God", 267). The primacy was given to Peter directly and immediately. So the Church has always understood -- and so Vatican I defined: "We therefore teach and declare that, according to the testimony of the Gospel, the primacy of jurisdiction over the universal Church of God was immediately and directly promised and given to Blessed Peter the Apostle by Christ our Lord. [...] And it was upon Simon Peter alone that Jesus after His resurrection bestowed the jurisdiction of chief pastor and ruler over all His fold in the words: "Feed My lambs; feed My sheep" ("Pastor Aeternus", Chapter 1).
The primacy is a grace conferred on Peter and his successors, the popes; it is one of the basic elements in the Church, designed to guard and protect its unity: "In order that the episcopate also might be one and undivided, and that [...] the multitude of the faithful might be kept secure in the oneness of faith and communion, He set Blessed Peter over the rest of the Apostles, and fixed in him the abiding principle of this twofold unity, and its visible foundation" ("Pastor Aeternus, Dz-Sch 3051"; cf. Vatican II, "Lumen Gentium", 18). Therefore, the primacy of Peter is perpetuated in each of his successors: this is something which Christ disposed; it is not based on human legislation or custom.
By virtue of the primacy, Peter, and each of his successors, is the shepherd of the whole Church and vicar of Christ on earth, because he exercises vicariously Christ's own authority. Love for the Pope, whom St. Catherine of Siena used to call "the sweet Christ on earth", should express itself in prayer, sacrifice and obedience.
18-19. According to Tradition, St. Peter followed his Master to the point of dying by crucifixion, head downwards, "Peter and Paul suffered martyrdom in Rome during Nero's persecution of Christians, which took place between the years 64 and 68. St. Clement, the successor of the same Peter in the See of the Church of Rome, recalls this when, writing to the Corinthians, he puts before them 'the generous example of these two athletes': 'due to jealousy and envy, those who were the principal and holiest columns suffered persecution and fought the fight unto death'" ([Pope] Paul VI, "Petrum Et Paulum").
"Follow Me!": these words would have reminded the Apostle of the first call he received (cf. Matthew 4:19) and of the fact that Christ requires of His disciples complete self-surrender: "If any man would come after Me, let him deny himself and take up the Cross daily and follow Me" (Luke 9:23). St. Peter himself, in one of his letters, also testifies to the Cross being something all Christians must carry: "For to this you have been called, because Christ also suffered for you, leaving you an example, that you should follow in His steps" (1 Peter 2:21).
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.