Church Fathers on John 21:19
Our Lord having made Peter declare his love, informs him of his future martyrdom; an intimation to us how we should love: Verily, verily, I say to you, When you were young, you girded yourself, and walked where you would. He reminds him of his former life, because, whereas in worldly matters a young man has powers, an old man none; in spiritual things, on the contrary, virtue is brighter, manliness stronger, in old age; age is no hindrance to grace. Peter had all along…
It is not easy to find any ready to pass at once from this life; and so he says to Peter, When you are old, you shall stretch forth your hand.
That is, shall be crucified. And to come to this end, Another shall gird you, and carry you where you would not. First He said what would come to pass, secondly, how it would come to pass. For it was not when crucified, but when about to be crucified, that he was led where he would not. He wished to be released from the body, and be with Christ; but, if it were possible, he wished to attain to eternal life without the pains of death; to which he went against his will, but…