After this he said to him, “Follow me.”
This call, “Follow me!” is offered to Peter to re-engage in the mission after he has been reconciled with Jesus on the beach. It is the same command given by Jesus to Peter, and the other disciples, at the beginning of this gospel.
Peter had denied Jesus 3 times at his arrest and questioning. Now, after his resurrection Jesus challenges Peter 3 times by questioning his love. When Peter responds that he does love Jesus then Jesus calls him to offer leadership and “feed my lambs”.
Forgiveness is required for Peter to move forward. And it is freely initiated and offered by Jesus. Free… but not cheap. Peter’s renewed commitment is to have a cost to it.