15 So when they had eaten breakfast, Jesus said to Simon Peter, "Simon, son of Jonah, do you love Me more than these?" He said to Him, "Yes, Lord; You know that I love You."He said to him, "Feed My lambs."
16 He said to him again a second time, "Simon, son of Jonah, do you love Me?"He said to Him, "Yes, Lord; You know that I love You." He said to him, "Tend My sheep."
17 He said to him the third time, "Simon, son of Jonah, do you love Me?" Peter was grieved because He said to him the third time, "Do you love Me?"And he said to Him, "Lord, You know all things; You know that I love You." Jesus said to him, "Feed My sheep.
Jesus was asking Peter exactly what he had claimed back in John 13:37-38 (and Luke 22:31-33), after which the Lord had prophesied the three denials.
The first two times the Lord asked Peter if he loved Him, He used the word agapao (total unselfish love). Peter responded with phileo (like, affection, brotherly love). Peter probably wasn't as confident after his denials. He didn't dare brag about his love. Jesus used agapao the first two times He asked, but the third time, He used Peter's word phileo.
Perhaps the Lord asked Peter three times to counteract the three denials?
Jesus used Simon (v. 15), Peter's natural birth name, not Stone (Peter) as he'd been renamed (John 1:42).
more than these (v. 15) — probably "more than these other disciples love Me"
lambs (v. 15) — believers young in the faith
sheep (v. 16) — more mature believers (1 Peter 5:2-3)
grieved (v. 17) — sorrow, contrition — not anger
You know all things (v. 17) — Peter knew Jesus knew more than he himself did about Peter's love. Earlier, Peter had claimed total devotion, but Jesus knew he would betray Him. Now Peter was humbled.
Self-confidence not only makes it likely that we will fall, but often puts us in a condition where falling is the only remedy.
The Greek word agapao designates volitional, responsible love that emanates not so much from emotions as from the soul and will. This is the sort of love one exercises in choosing to love those whom one would not naturally love. This is the kind of love God has for the world, a divine love. The Greek word phileo designating the action of love that emanates from liking someone or something, conveys the idea of fondness. Peter, quite honestly, told Jesus that he was fond of Him. Peter could not say that his love was an agape love. When Jesus asked him the third time, he asked if he was fond of Him. Peter told Jesus what he already knew: "I am fond of You."
Each time Peter told Jesus "I am fond of You," Jesus exhorted Peter to care for His sheep. This is expressed in three ways: (1) "Feed My lambs," (2) "Take care of My sheep," and (3) "Feed My sheep." Again, one could argue that the verbal variation does not produce any meaning variation, but John used different terms for the sheep: arnia (lit., "young lambs" and "little sheep" — a term of endearment) and probata (the usual term for an adult sheep). Peter was charged to both care for them by feeding (boske) and shepherding (poimane). — Opening the Gospel of John, by Philip W. Comfort and Wendell C. Hawley, page 337-338