Verse 1
1) "Forasmuch then as Christ hath suffered for us in the flesh." Peter concludes that Jesus Christ has suffered in the flesh, on the believer’s behalf, and that such suffering should elicit loyalty and gratitude and willingness to suffer from his children, Luke 24:46; Acts 3:18; 2 Timothy 2:12; 2 Timothy 3:12; 1 Peter 2:21.
2) "Arm yourselves likewise with the same mind." (Greek hoplisasthe) arm or fortify yourselves with (hauten) the one of the same mind or disposition -- a willingness to suffer for Him. Philippians 2:5-7.
3) "For he that hath suffered in the flesh." (Greek hoti ho pathon) the one having suffered (Christ) in the flesh, Hebrews 2:18; Hebrews 5:8; Isaiah 53:5.
4) "Hath ceased from sin." Has terminated his subjection to the power and presence of sin over him -- the sins of others having borne, Hebrews 9:25-26. Thus he cried, "it is finished." John 19:30.