"18 Truly, truly, I say to you, when you were young, you used to dress yourself and walk wherever you wanted, but when you are old, you will stretch out your hands, and another will dress you and carry you where you do not want to go.” 19 (This he said to show by what kind of death he was to glorify God.) And after saying this he said to him, “Follow me.”"
John 21:18-19
What does our Lord refer to in 18? The words have both a literal and also a metaphorical, spiritual significance. On the one hand, here is a simple statement about the physical freedom enjoyed by a young man; he is his own master, he can do what he likes. But when he becomes old, he is restricted, and no longer is able to do the things he did as a young man. But the underlying, spiritual meaning, on the other hand is that these words describe the sort of man Peter had been up to that time, self-willed and independent, his own master. And John makes very plain in 19 that Jesus it referring to the kind of death Peter was to die. In this connection, we should look back to 13:36-38, to words spoken of Peter's imminent denial. Jesus said that Peter could not follow Him then, but would thereafter. It seems that it is this that Jesus is referring to here, hence the words at the end of 19, 'Follow Me'. The words of Jesus were fulfilled in a twofold way: it is true in a literal sense that Peter was in fact crucified and became a martyr for the name of Jesus. But it is just as true that when Jesus said, 'Follow Me' He was calling Peter to walk the way of the cross - the thing that up to that point he had never done. This is the real fulfilment of the 'Lovest thou Me?' questions. Jesus is saying, in effect, that in contrast to what Peter had been, the cross would now henceforth become the principle of his life. It is significant that at the outset of our Lord's ministry, these were the words - 'Follow Me' - with which He had first called the disciples (1:43). Between that point and this, we have the whole exposition of what that command really means and involves; discipleship based on the cross. With what tremendous significance, therefore, is this second 'Follow Me' filled.