Today's passage is among the most difficult in the New Testament.  It deals with the time between the death and resurrection of the Lord Jesus Christ.  When He was put to death, His body died and was buried.  But when He was seen again alive, He was in a very different kind of body - one in which He could appear through locked doors and disappear again, although still bearing the marks of His wounds on the cross (John 20:25).  

Christ’s resurrection body gives us an insight into the new bodies which all believers will occupy when Jesus comes again, as Paul describes in 1 Corinthians 15:35-53.  Paul’s purpose was to encourage Christians to stand firm in Jesus, not deflected from their gospel purpose by persecution even though death might come, because we all who are in Christ will all share in the resurrection victory of Christ and wear a resurrection body like His (1 Corinthians 15:54-58).     

Peter’s purpose in these verses is the same, to comfort those suffering for their faith and to encourage them to keep faithful and not be disobedient like those in Noah’s day.  Those people had so much opportunity to respond to the ‘preacher of righteousness’, as did the fallen angels, but they refused (2 Peter 3:4-5).  Their gross folly was confirmed to them by the living Lord Jesus when He descended into hell, to proclaim His victory over death, as they continued to await their final judgement.  But Noah obeyed the Lord and was saved (Hebrews 11:7), a forerunner of many who would obey the gospel and be assured of being raised with Christ on the Final Day (John 6:39-40).

Today's verses contain mysteries we will not fully understand until we see Jesus, face to face (1 Corinthians 13:12).  But one thing is certain.  The dead Jesus was made alive by the Spirit, and He is still powerfully alive.  This truth should inspire us now, because, "And if the Spirit of him who raised Jesus from the dead is living in you, he who raised Christ from the dead will also give life to your mortal bodies through his Spirit, who lives in you." (Romans 8:11).  In other words, all those who have the Holy Spirit in them will have His power to help them live the Jesus-life in their bodies now, and they will wear a resurrection body when Christ returns.  That is true whatever trouble may come, and even death cannot separate us from His love (Romans 8:37-39).  It may seem too good to be true - but it is very good and very true ... you have God's Word!