"Gird" is the more accurate translation of ζώννυμι.
In other words, Jesus was not concerned about whether Peter would be dressing himself or not, as ecclesiastical translators of the NIV, NLT, ESV and other Bible translations would have us believe.
Yes, we don't typically use the word gird in modern English. But in those times people referred to girding because it was typically necessary to stabilize whatever clothing or armor one was wearing in order to keep it from falling off. During the time of Jesus, robes were often the typical clothing, and they were girded with rope among the less wealthy. The wealthier classes often girded their clothing with fancier belts and tassels.
What does this have to do with Jesus' point?
Jesus is using the concept of girding both in the sense of clothing and in the sense of the ability to stabilize ones body. Girding symbolizes binding clothing to the body, but also, in Jesus' second use of the word, the body itself being bound or girded.
Jesus is also discussing Peter's freedom to move about: "when you were younger, you... walked where you wished."
Now Jesus is stating that when Peter's body grows old, he will no longer be able to walk where he wished, because, "another will gird you and carry you where you do not wish."
This can only take place under two scenarios: Either Jesus is speaking of Peter growing so old that he won't be able to take care of himself, or that he will be imprisoned.
The kind of prison stated here relates to being bound in chains - as many prisoners were in those days. When one is bound and shackled, there is no opportunity to travel freely, and there is no opportunity to dress oneself.
The Book of John then states:
Jesus said this to indicate the kind of death by which Peter would glorify God. (John 21:19)The early Christian teacher Origin wrote about Peter's eventual death:
"Peter was crucified at Rome with his head downwards, as he himself had desired to suffer." (From Leo the Great 440-461)This is consistent with Jesus' prophesy: "you will stretch out your hands, and another will gird you and carry you where you do not wish."
Stretching out ones hands would be appropriate to crucifixion, just as the concept of "another will gird you" because in this case, the reference to gird would relate to the body being girded to a cross.
As Origin wrote, and as put forth by other early Christian teachers, Peter would be imprisoned in his later years by the Romans due to his incessant teachings, and the Romans eventually crucified him. But because Peter felt himself unworthy of being crucified as Jesus had been, he requested the cross be turned upside down.
This documents part of the life of a dedicated follower. And indeed, Jesus confirmed this, as he emphatically instructed Peter:
"Follow me!"But did Jesus mean that he wanted Peter to follow Jesus into crucifixion?
Certainly not, as this would be imitation, and suicide if willingly carried to ones death. And certainly those who make shows of self-infliction and self-crucifixion among some ecclesiastical institutions around the world are certainly not doing what Jesus instructed Peter to do when he said: "Follow me!"
Jesus wanted Peter to carry on his teachings. Jesus wanted Peter to dedicate his life to Jesus' teachings, and then pass on those teachings to others.
This is also how Peter "glorified God" with his life, and death of his physical body: by his loving service to the Supreme Being.
You see, spiritual life is not about becoming a great teacher or having lots of followers, or becoming famous for being such a great spiritual person, or being the big man in a church or other organization.
Spiritual life is about re-developing ones personal loving relationship with the Supreme Being.
In other words, spiritual life is about love. It is about loving the Supreme Being.
And just how is love expressed? It is expressed with loving service.
We can see this even among mundane relationships of this world. When someone cares about another person they will do things that please the other person.
This is called service. And it is inseparable from love.
And this is the sum and substance of spiritual life: Loving service to the Supreme Being.
This is why Jesus said about his own service:
“My food, is to do the will of Him who sent me and to finish His work." (John 4:34)Why would Jesus say that doing God's will is his food? Because food symbolizes becoming fed or fulfilled. Jesus is stating that he becomes fulfilled when he does God's will. Why?
Because Jesus loves the Supreme Being. He cares about Him. He wants to do what pleases his beloved God.
This is the secret of spiritual life. Spiritual life is not about being saved or going to heaven. Spiritual life is about wanting to please the Supreme Being. This is called love.
And it is this love, and loving service to the Supreme Being that Jesus wanted Peter to follow. Jesus wanted Peter to "finish His work" by passing on Jesus' teachings to others. And as Peter did this, he glorified the Supreme Being not only by passing on Jesus' teachings, but with his entire life of loving service, which included the death of his physical body.
And what was the most important teaching of Jesus?
“‘Love the Lord your God with all your heart and with all your soul and with all your mind.' This is the first and greatest commandment." (Matt. 22:37-38)