"He saith unto him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said unto him the third time, Lovest thou me? And he said unto him, Lord, thou knowest all things; thou knowest that I love thee. Jesus saith unto him, Feed my sheep." (John 21:17)
Our Lord over the breakfast of roasted fish and bread turned to Peter and asked him a question three times. In the literary context of the Torah and the prophets, we can see that it's the Lord who repeats a question three or more times. The Lord asked Elijah the same question three times, "“What are you doing here, Elijah?” God called Samuel three times before revealing His plans to him. Peter encountered the same voice that called out to the Old Testament saints. This time the question was different. "Simon, son of Jonas, lovest thou me?" God made His intentions clear. The Creator designed and formed humans to be a storehouse of His love. He desires nothing back from us other than pure sincere love. Thus He asked His disciple who was a leader in all respects to reiterate his commitment to the Lord. He was the one who led the disciples back to the sea but after these moments, Peter would be leading the folks in doing a greater blessed work and that was to feed the sheep of Christ.
Our Lord is the good shepherd and His sheep had to be fed with the word. Peter thus always had a heart for pastors and specially in his epistles, he devoted specific sections as guidelines for pastoral ministry. St. Peter transformed from being a fisherman to being a shepherd as the Lord spoke to him intimately. St. John presents this incident as the final of all proofs to his readers to establish the fact that Jesus is the Son of God. May we hear the heart and voice of the Lord seeking our love. If we love Him, we will devote time and efforts to feed His sheep and would model before them a Christ-centric life.For further reading: 1 Peter 5:1-4, Jeremiah 3:15