1 Peter 4:1

The apostle here draws a new inference from the consideration of Christ's sufferings. As he had before made use of it to persuade to patience in suffering, so here to mortification of sin. Observe, I. How the exhortation is expressed. The antecedent or supposition is that Christ had suffered for us in the flesh, or in his human nature. The consequent or inference is, "Arm and fortify yourselves likewise with the same mind, courage, and resolution." The word flesh in the former part of the verse signifies Christ's human nature, but in the latter part it signifies man's corrupt nature. So the sense is, "As Christ suffered in his human nature, do you, according to your baptismal vow and profession, make your corrupt nature suffer, by putting to death the body of sin by self-denial and mortification; for, if you do not thus suffer, you will be conformable to Christ in his death and resurrection, and will cease from sin." Learn, 1. Some of the strongest and best arguments against all sorts of sin are taken from the sufferings of Christ. All sympathy and tenderness for Christ as a sufferer are lost of you do not put away sin. He dies to destroy it; and, though he could cheerfully submit to the worst sufferings, yet he could never submit to the least sin. 2. The beginning of all true mortification lies in the mind, not in penances and hardships upon the body.

— Matthew Henry's Concise Commentary (public domain)