What does John 21:17 mean?

If Peter did not understand what Jesus meant by repeating His questions about love, he certainly understands now.

Jesus miraculously provided fish when He called Peter to be a disciple (Luke 5:5–11). He recently repeated that act, reminding Peter of his initial calling (John 21:4–8).

Peter once bragged that he would be loyal to Jesus even when others were not (Mark 14:29). Jesus started this conversation by pointedly asking if Peter loved Him more than the other disciples (John 21:15).

Only a few days prior, Peter had declared—three times, with great emphasis—that he did not know Jesus (John 13:35–38; Luke 22:61–62). Jesus has already repeated His question: "do you love Me?" twice, and now asks for a third time. This last question is even more piercing. In the first two questions, Jesus' reference to love used the Greek term agapaō. Both of Peter's answers used the closely related term phileō. Now, Jesus uses the exact same word as Peter. For this third question, Jesus is asking Peter "do you [phileō] me," after Peter has just said, twice, "I [phileō] you."

The implication is clear: Peter has said this very thing, twice, using those exact words, but Jesus wants to hear it a third time. Peter's response is to be "grieved," the same term used to describe Jesus' emotion in Gethsemane (Matthew 26:37). He understands that Jesus is not asking because He does not know; He is asking to prove a point. Three denials are being countered with three affirmations. Peter's betrayal of his own promises is being challenged.

Jesus will not leave Peter in sorrow, however. This is a moment of repentance and restoration. His next words predict that Peter's reaffirmed faith (John 21:19) will be permanent—in fact, it will lead to martyrdom (John 21:18).