Jesus said this to indicate the kind of death by which Peter would glorify God. Then he said to him, “Follow me!”
Peter is going to glorify God by his death, just like Jesus (John 12:23, 15:8). Our admonition is to glorify Jesus, whether in our living or in our dying (Php 1:20).
John 12:23 Jesus replied, “The hour has come for the Son of Man to be glorified.
John 15:8 This is to my Father’s glory, that you bear much fruit, showing yourselves to be my disciples.
Philippians 1:20 I eagerly expect and hope that I will in no way be ashamed, but will have sufficient courage so that now as always Christ will be exalted in my body, whether by life or by death.
Jesus ended His prophecy to Peter with an admonition to follow Him, which could have several meanings. The tense of the verb is present, meaning “Keep on following Me!” Peter had followed Christ in the past, although not always continuously, and Jesus was encouraging him to steadfastly follow Him in the future in all of his ways. This would have been a further confirmation to Peter of his complete restoration by Jesus, for this was the same call made to him under quite similar circumstances years before (Matt 4:18-20). In fact, this is the same call that is made to every disciple of Christ, even today (Matt 16:24).
Matthew 4:18-20 As Jesus was walking beside the Sea of Galilee, he saw two brothers, Simon called Peter and his brother Andrew. They were casting a net into the lake, for they were fishermen. “Come, follow me,” Jesus said, “and I will make you fishers of men.” At once they left their nets and followed him.
Matthew 16:24 Then Jesus said to his disciples, “If anyone would come after me, he must deny himself and take up his cross and follow me.
In another sense, this was a command to Peter to do what Jesus had done (John 15:20). He had given them (and us) an example of how to live and how to die (1 Peter 2:21).
John 15:20 Remember the words I spoke to you: ‘No servant is greater than his master.’ If they persecuted me, they will persecute you also. If they obeyed my teaching, they will obey yours also.
1 Peter 2:21 To this you were called, because Christ suffered for you, leaving you an example, that you should follow in his steps.
Jesus may have spoken this command to Peter as He was rising from the table, thus indicating to Peter to follow Him as He walked a short distance away from the others. This would be supported by the next verse where it is mentioned that John was following them.
Finally, this is also the repetition of a promise Jesus had previously made to Peter (John 13:36). Henry comforts us by saying “Those that faithfully follow Christ in grace shall certainly follow him to glory.” Are you following Jesus?
John 13:36 Simon Peter asked him, “Lord, where are you going?” Jesus replied, “Where I am going, you cannot follow now, but you will follow later.”