Always bearing about in the body the dying of the Lord Jesus. — The word for “dying” (again, probably, a distinctly medical term) is literally “deadness,” “the state of a corpse.” Comp. Romans 4:19 for the word itself, and Romans 4:19; Colossians 3:5 (“mortify”), Hebrews 11:12 (“as good as dead”) for the cognate verb. The word describes, as by a bold hyperbole, the condition of one whose life was one long conflict with disease: “dying daily” (1 Corinthians 15:31); having in himself “the sentence,” or, possibly, the very symptoms, “of death” (2 Corinthians 1:8-9). He was, as it were, dragging about with him what it was scarcely an exaggeration to call a “living corpse;” and this he describes as “the dying” (or death-state) “of the Lord Jesus.” The thought implied in these words is not formally defined. What seems implied is that it brought him nearer to the likeness of the Crucified; he was thus made a sharer in the sufferings of Christ, filling up what was lacking in the measure of those sufferings (Colossians 1:24), dying as He died, crucified with Him (Galatians 2:20). It may be noted that Philo (2 Alleg. p. 73) uses almost the same word to express the natural frailty and weakness of man’s body — “What, then, is our life but the daily carrying about of a corpse?”
That the life also of Jesus... — The life of Jesus is the life of the new man, “created in righteousness and true holiness” (Ephesians 4:24). It is not that the Apostle is merely looking forward to the resurrection life, when we shall bear the image of the heavenly; he feels that the purpose of his sufferings now is that the higher life may, even in this present state, be manifested in and through them; and accordingly, as if to guard against the possibility of any other interpretation, he changes the phrase in the next verse, and for “our body” substitutes “our mortal flesh.”