17 The third time he said to him, "Simon son of John, do you love me?" Peter was hurt because Jesus asked him the third time, "Do you love me?" He said, "Lord, you know all things; you know that I love you."
What a strange conversation between Jesus and Peter; Jesus repeatedly asking Peter if he loved him--Peter becoming hurt and perplexed at Jesus' questions--and Jesus already knowing the answer, as Peter pointed out.
Each time Peter answered, "Yes," Jesus told him to feed his sheep or lambs.
Peter and six other disciples had been fishing. Because Peter's business was fishing before he left it all to follow Jesus, it's possible that when Jesus was crucified, he felt a chapter of his life was closed and he went back to what he knew.
This fishing trip was disappointing--they caught no fish--until the "stranger" on the shore called out to them to put down their nets on the other side of the boat--and then they caught a whopping 153! I wonder if this felt eerily familiar to Peter. What happened that day mirrored something that happened at the start of Jesus' ministry and is recorded in the book of Luke chapter 5, in verses 1-11. It's Jesus' original call to Peter, which involved leaving his fishing business and becoming a fisher of men.
The fish that Jesus was cooking on the beach had not been caught by the men in the boat. Jesus fed them and then he reminds Peter of who he is--a fisher of men, not aquatic animals. "Feed my sheep," he tells him.
Then Jesus gives Peter a picture of his mortality.
John 21:18-19 (New International Version)
18 Jesus said, "Feed my sheep. I tell you the truth, when you were younger you dressed yourself and went where you wanted; but when you are old you will stretch out your hands, and someone else will dress you and lead you where you do not want to go." 19 Jesus said this to indicate the kind of death by which Peter would glorify God. Then he said to him, "Follow me!"
Time is finite--life and opportunities to be seized and used now. Jesus repeats the words of what was his call to Peter all along--his call to me, too..."Follow me."