4:1 since Christ suffered physical pain: Peter introduced this idea in 3:18; he now indicates its significance in Christian experience. In our own physical sufferings, we are to imitate Christ’s attitude (see 2:21-24). Our suffering with Christ shows that we have identified with him (see Rom 8:17). Those who identify with Christ experience the victory over the power of sin that he won on the cross (Rom 6:1-10).

4:11 All glory and power to him forever and ever! Amen: This doxology has led some to suggest that one original letter of Peter ended here and that another one was added to it. Doxologies in the New Testament do appear at the end of letters (Rom 16:25-27; Phil 4:20; Heb 13:21; 2 Pet 3:18; Jude 1:24-25), but also at the end of sections within letters (Rom 11:36; Gal 1:5; Eph 3:21; 1 Tim 1:17). Since there is no textual evidence for the existence of two separate letters, it is better to assume that this doxology marks the end of a major section of the letter.