It has been suggested by no less than St. Augustine that Jesus queried Peter about his love for Him three times to atone for the three times Peter had denied Him.
Who am I to argue with Augustine? Plus, it makes seems to match the gracious way God deals with those who have sinned. Sins need to be confessed to be forgiven and until they are acknowledged they cannot be repented of.
Only what gets surrendered gets blessed and only what gets confessed gets forgiven.
So grace is a theme of this story without a doubt. But there are also some powerful lessons on Godly love.
First, notice how Godly love is defined. The love Jesus required of Peter (as well as you) is "agape" which is a surrendered, sold out, and sacrificing love. "Agape" is the unconditional supernatural love that resides in the nature of God but which He longed to impart to Peter (as well as you).
Second, notice how Godly love is demonstrated. Jesus made it clear to Peter why he needed this "agape" love. Godly love is demonstrated through serving. Jesus said, “Feed my lambs” , a second time He said, "take care of my sheep" and then He said, "feed my sheep".
But there is a second way "agape" love is demonstrated. Jesus told Peter that his ultimate expression of Godly love would be in suffering for the Faith, just as Jesus' love would demonstrated by His suffering on a cross.
"Agape" is defined by sacrifice and demonstrated by suffering. It comes from God through Christ.
Jesus had it. Peter got it.
What about you?