The warning of what awaited him, which the Lord here gave to Peter, was divinely adapted to his peculiar cast of mind, and in conjunction with the words, "Follow Me," was fitted at once to console and solemnise the apostle.
I. "When thou wast young thou girdedst thyself." Rapidity and self-reliance have always been your way. "But" and there must have been something in the way in which this was spoken which conveyed a peculiar import, for it was at once understood as predicting to Peter a death like Christ's own "But when thou shalt be old, another shall gird thee," etc. And whilst we can quite believe that to the eager disciple, so full of revenge at himself and of devotion to his Lord, there was at this fervid moment joy in the prospect of being conformed to Christ in His crucifixion, in conjunction with all that had occurred, it was a sobering consideration that the days of freedom and self-disposal were about to be succeeded by days of captivity and a death of violence.
II. But by that death he should glorify God. It is a singular history, older than the time of Peter, as old, we may say, as the death of Abel, and accounted for by man's mournful antipathy to God's holiness and God's truth; in this world of ours, when any stands out from his fellows severely loyal to his God, that constant tendency to exclaim: "Away with such a fellow from the earth" that perpetual effort to extirpate unwelcome truth by slaying and burying out of sight the witness-bearer. Yet in all these martyrdoms God is glorified. We wonder how weak humanity survived such tragedies; and as we think of all whom the headsman's axe left widows, and all whom inquisitorial terrors hunted from their homes, and try to estimate that long agony by which a martyr Church has maintained its testimony, we begin to appreciate the awful privilege assigned to Peter and to the myriads who, like him, have trod in the Master's bleeding track since that morning when, stretching forth His own pierced hands, Jesus said to the apostle, "Follow Me."
J. Hamilton, Works,vol. i., p. 304.
Reference: John 21:18; John 21:19. E. M. Goulburn, Thoughts on Personal Religion,p. 227. John 21:18-23. Homilist,vol. v., p. 173.