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 unto thee, When thou wast young, thou girdedst thyself, and walkedst whither thou wouldest. 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 desired to share Christ’s dangers; so Christ tells him, Be of good cheer; I will fulfil thy desire in such a way, that what thou hast not suffered when young, thou shalt suffer when old: But when thou art old. Whence it appears, that he was then neither a young nor an old man, but in the prime of life.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: Hom. lxxxvii