You hear this passage a lot in church.
Jesus, after His resurrection, stands on the shore of the Sea of Tiberias (more of a lake really) and calls out to Peter. Peter, in a ship with six other disciples, fishing by net. It's early morning. John ("that disciple who Jesus loved") realizes it's Jesus before anyone else, and Peter, full of the same vim and vigor he displayed on the Sea of Galilee, jumps out of the ship, leaving the other disciples to row to shore, while he swims to Jesus. He arrives first and Jesus has, around a fire, laid out breakfast for them. "Come and dine", He says (John 21:12). After eating, Jesus decides to grill (kindly) Peter regarding the depth of his love for Him. The funny thing about the next part of this passage is that, rendered in English, one is likely to miss what the text is meant to convey. Jesus asks Peter: "Lovest thou me more than these?" (verse 15, referring to the other disciples) Before we go any further, it's an interesting question for Jesus to ask. He's not playing favorites, He's more-or-less having Peter eat his words. In Mark's gospel (14:29), Peter boldly declares, "Although all shall be offended, yet will not I." It was foretold that all would forsake Jesus prior to His crucifixion. It's the nature of the beast, join the club. Now Jesus wants to see if Peter knows what it means to love through thick and thin. So He asks Him: "Lovest thou me more than these?" To which Peter responds in kind: "Yea, Lord; Thou knowest that I love Thee." Jesus answers: "Feed my lambs". Jesus asks a second and a third time and by that time, it says that "Peter was grieved because He said unto him the third time Lovest thou me?" (verse 17) Anyone would be perturbed were they asked the same thing three times in a row, had they given, what they thought, was the correct answer.
And this is where an English translation doesn't do the text justice. Jesus asks "do you love me?" The Greek word for "love", in this case, is agape. It's a broad and deep word befitting the love that Jesus has for us. Jesus is essentially asking if the depth of Peter's love includes "heart, soul, mind and strength" as enumerated by Jesus in Mark's Gospel (12:30) That's what the word entails: loving with all of you. It's what God gave, it's what God requires. The next verse (12:31) uses the same: "Thou shalt love (agape) thy neighbor as thyself." But when Peter answers Jesus, seated around the fire on the shore, ("yea, Lord; Thou knowest that I love Thee.") Peter's using a weaker, more watered-down pseudo-synonym: Fileo. It means "fondness". It's as if Jesus is asking Peter if he loves Him, to which Peter is responding, "Yes, Lord, you know that I like you a lot." Maybe he feels he can't use a stronger word? Who knows.
"Greater love hath no man than this, that a man (or woman) lay down his life for his friends." (John 15:13)
Who knows why Peter couldn't say it outright. Admittedly, they weren't speaking Greek, they were speaking Aramaic. Though a literal Aramaic-to-English translation doesn't really help in this case because it reads "love" in both instances as well. And this brings up an interesting point as the word "love" means so many things to different people. Just like "truth", love is defined as God defines it. You know it when you see it and when you feel it. "Hereby shall all men (and women) know..." (John 13:35, emphasis mine) Another true test of love is its staying power. "Charity (agape) never faileth..." (1 Corinthians 13:8) You know it's love after you've thrown everything you can at it (them) and they choose to remain. They choose to continue loving selflessly. Three times does Peter answer and three times Jesus tells him, "feed my sheep". Okay, the first time it's "feed my lambs". They're growing, you understand. So are we.
Then after another brief conversation, He tells Peter "follow me." (verse 19) Loving Jesus means giving up everything to serve and follow Him. Beginning with our own notions of what love is and what it should be.
He'll show you.