Jesus said this to indicate the kind of death by which Peter would glorify God. John 21:19 (NIV)
We know from history that Peter was crucified in Rome, somewhere around the year 64 AD. That’s 30 years after the death and resurrection of Jesus.
This means Peter served Jesus for 30 years with this prophecy hanging over him. He poured his life into ministry knowing that, at the end, he would find himself in a prison cell facing a public execution. He knew that these things would happen, but he followed Jesus anyway.
This shines fresh light on what Peter says in his two New Testament letters, which were written as a great wave of persecution under emperor Nero was breaking out.
Dear friends, do not be surprised at the painful trial you are suffering, as though something strange were happening to you (1 Pet. 4:12 NIV). Peter wasn’t surprised.
I think it is right to refresh your memory as long as I live in the tent of this body, because I know that I will soon put it aside, as our Lord Jesus Christ has made clear to me (2 Pet. 1:13-14 NIV). Peter knew what was coming.
Do you feel challenged by Peter’s example? If you knew that your life would end with great suffering, would you follow Christ wholeheartedly now? If you knew that your ministry would bring you great pain, would you pour yourself into serving Christ anyway?