1 and 2 Peter
The theme of 1 Peter is suffering and the glory to follow. It is written to the Jewish believers what are scattered and will go through the Tribulation. In the time of the Tribulation there will be intense persecution because of one's faith in Christ.
Peter writes to them about the hope that they have because of the resurrection of Jesus Christ from the dead; there will be salvation for those who endure until the end. In Hebrews 12:2, Jesus endured the cross (suffering) by the joy that was set before him (glory to follow the suffering). The suffering will be intense but only for a season.
There will be no escape from the Tribulation but the trial of faith will bring glory and honor at the appearing of Christ.
Why the suffering is necessary:
(1 Peter 5:10 KJV) But the God of all grace, who hath called us unto his eternal glory by Christ Jesus, after that ye have suffered a while, make you perfect, stablish, strengthen, settle you
This Epistle written by Peter is to help the Tribulation Saints answer the question, "Where is the promise of His coming?" In the early Chapters of Acts the prophetic timetable is moving along on schedule according to prophecy, it was almost the time for the Kingdom of God to be set up on earth, when Christ who was raised from the dead would sit on the throne of David.
1 Peter tells about the glory that is to come and then, as we read in the book of Acts, the signs and wonders begin to taper off and the rest of Joel's prophecy that Peter spoke about on the day of Pentecost does not happen.
2 Peter is written in light of this delay, it explains the longsuffering of God and that God has interrupted the prophetic program. Peter writes this Epistle because he knows that the prophetic program was temporarily set aside but it will continue.
Those going through the Tribulation will have to be aware of the false teachings that will be taught such as Jesus is not the Christ, and if He promised to return then why has He not yet appeared? Peter tells them that the judgement of God will come and God is not slack concerning His promises. God withheld His wrath so that all should come to repentance. When Israel rejected God's plan for them and stoned Stephen the world was deserving of God's wrath. Peter understood the longsuffering of God. The writings of Apostle Paul help us understand why the world has not yet experienced the wrath of God.