John Chrysostom — as excerpted in the Catena Aurea on John 21:18-19

“(Hom. lxxxviii) He says, Whither thou wouldest not, with reference to the natural reluctance of the soul to be separated from the body; an instinct implanted by God to prevent men putting an end to themselves. Then raising the subject, the Evangelist says, This spake He, signifying by what death he should glorify God: not, should die: he expresses himself so, to intimate that to suffer for Christ was the glory of the sufferer. (non occ.). But unless the mind is persuaded that He is very God, the sight of Him can in no way enable us to endure death. Wherefore the death of the saints is certainty of divine glory.”