Peter had denied ever even knowing Jesus at the moment of His greatest need. Jesus knew Peter would deny Jesus, and now, after it was all said and done, Peter knew it, too.
But when Jesus came back from the dead He didn't just reappear to some of the disciples and tell them to spread the word. Jesus told them specifically to tell Peter. Jesus called Peter by name.
Later, Peter and the disciples were fishing, Jesus tells them how to catch the fish (again), He calls them all on shore for breakfast, and it's all Cokes and jokes until breakfast is over and Jesus ask a question. "Do you love me?"
And Jesus already knew the answer.
Miraculous - John 21:1-19