Charles Spurgeon Commentary John 21:17-19

"He saith unto him the third time, Simon, [son] of John, 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. Verily, verily, I say unto thee, When thou wast young, thou girdedst thyself, and walkedst whither thou wouldest: but when thou shalt be old, thou shalt stretch forth thy hands, and another shall gird thee, and carry thee whither thou wouldest not. Now this he spake, signifying by what manner of death he should glorify God. And when he had spoken this, he saith unto him, Follow me." — John 21:17-19 (ASV)

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. Verily, verily, I say unto thee, When thou wast young, thou girdedst thyself, and walkedst whither thou wouldest: but when thou shalt be old, thou shalt stretch forth thy hands, and another shall gird thee, and carry thee whither thou wouldest not. This spake he, signifying by what death he should glorify God. (John 21:17–19)

Peter was to stretch out his hands, and be nailed to a cross, as his Lord was.

Jesus says to him, Feed my sheep. Verily, verily, I say to you, When you were young, you girded yourself and walked where you wished; but when you are old, you will stretch out your hands, and another will gird you and carry you where you would not wish to go. He spoke this, signifying by what death he was to glorify God. And when he had spoken this, he says to him, Follow me.

Peter's death was to glorify God, so he might well be content, painful though it was to be.