Verily, verily, I say unto you, When you were young, you dressed yourself, and walked where you would: but when you shall be old, you shall stretch forth your hands, and another shall dress you, and carry you where you would not.
All Commentaries on John 21:18 Go To John 21
George Leo Haydock
AD 1849
Thou shalt stretch forth thy hands . signifying by what death he should glorify God; that is, that a cross should be the instrument of his death and martyrdom.
Whither thou wouldst not: which is no more than to say, that a violent death is against the natural inclination of any man, even though he be ever so willing, and disposed to undergo it. (Witham)
By this is meant the martyrdom of St. Peter, which took place thirty-four years after this. He was first cast into prison, and then led out to punishment as Christ had foretold him. He stretched out his arms to be chained, and again he stretched them out, when he was crucified; for he died on the cross, as the ancients assure us. (Calmet)