Life got off balance for Peter. The same happens to us. I know, personally, I have been off balance. I feel like God has restored me. He brought me back to where He wants me to be. This is what He does. He did this for Peter too.
Jesus refuses to leave us where we are. Thank goodness!
After He resurrected, He went to find the disciples. Guess where they were... in Tiberias, fishing! That's right, they went to the city of rejection and challenging times and right back to their old life. They were defeated, distraught, and depressed. The man they followed was gone.
Jesus saw them fishing in John 21, the first thing He called them was "FRIENDS". They had betrayed Him, left Him in His time of need, etc... and He called them friends.
He told them to put the nets on the other side because they had not caught anything all night. It was almost exactly like when He first called them. Then He told them He wanted them to be fisher of men. This was His way of restoring them and helping them understand what He wanted them to do. Now, Peter, jumped out of the boat ahead of everyone. (I think of Forrest Gump jumping off his boat when he saw Lt. Dan!) Peter might have done that because he thought Jesus was about to give him a tongue lashing. That's not what Jesus did.
There were coals burning and fish cooking for breakfast. Peter had warmed himself by coals the night he denied Jesus. Three times in this chapter, Jesus asked Peter if he loved Him. Peter actually was getting upset. Peter said, "Lord, you know all things. You know that I love you." It was Jesus restoring Peter for those three denials.
We all mess up and deny Jesus at times. Thankfully, He restores us. He loves us too much to leave us in that mess. What an awesome God we have!