In today's Gospel reading, Jesus visits His disciples by the sea. He again breaks bread with them and shows Himself literally, bodily raised from the dead. There is another time of fellowship. The resurrection of Jesus completes the picture of our reconciliation with God. When we were once far off, we are drawn near to the Father through the Son. Alienation is replaced with close intimacy.
In the passage today, the disciples catch a huge quantity (some translations refer to a 'draught', which I very much like) of fish at the very word of Jesus. This hearkens back to when Peter was first called to follow the Lord (Luke 5:1-11). As Peter's future comes more clearly into view, he is reminded of how he first came to see that Jesus was calling him to something more than fishing in the Sea of Galilee. Jesus was calling Peter to be a 'fisher of men'.
Peter would indeed lead the disciples in taking the words of eternal life out into the world. They would drag a net over the earth, harvesting more disciples. I think the draught of fish symbolizes what will happen as the Gospel of Jesus goes forth. There will be such a huge haul that they would scarcely be able to handle it. And all this by God's grace. The harvesters, the net, and the sinews holding together not by human power, but by the continual act of divine love and mercy. From the day many years ago that we read about in John 21 until this very moment, the 'net of grace' has been roving too and fro across the earth.