"The Savior again gives a brief response, but with relentless scrutiny He asks for the third time, 'Peter, do you love me?' By now surely Peter is feeling truly uncomfortable. Perhaps there is in his heart the memory of only a few days earlier when he had been asked another question three times and he had answered equally emphatically—but in the negative. Or perhaps he began to wonder if he misunderstood the Master Teacher’s question. Or perhaps he was searching his heart, seeking honest confirmation of the answer he had given so readily, almost automatically. Whatever his feelings, Peter said for the third time, “Lord, … thou knowest that I love thee.”
“'Then Peter, why are you here? Why are we back on this same shore, by these same nets, having this same conversation? Wasn’t it obvious then and isn’t it obvious now that if I want fish, I can get fish? What I need, Peter, are disciples—and I need them forever. I need someone to feed my sheep and save my lambs. I need someone to preach my gospel and defend my faith. I need someone who loves me, truly, truly loves me, and loves what our Father in Heaven has commissioned me to do. Ours is not a feeble message. It is not a fleeting task. It is not hapless; it is not hopeless; it is not to be consigned to the ash heap of history. It is the work of Almighty God, and it is to change the world. So, Peter, for the second and presumably the last time, I am asking you to leave all this and to go teach and testify, labor and serve loyally until the day in which they will do to you exactly what they did to me.'”
"...My beloved brothers and sisters, I am not certain just what our experience will be on Judgment Day, but I will be very surprised if at some point in that conversation, God does not ask us exactly what Christ asked Peter: 'Did you love me?' I think He will want to know if in our very mortal, very inadequate, and sometimes childish grasp of things, did we at least understand one commandment, the first and greatest commandment of them all—'Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind.' And if at such a moment we can stammer out, 'Yea, Lord, thou knowest that I love thee,' then He may remind us that the crowning characteristic of love is always loyalty.
-E. Jeffrey R. Holland.
Read this entire talk here.