Revelation 2:8–11 contains Jesus’ message, through John, to the church at Smyrna. Christians in Smyrna were undergoing intense persecution at the time these words were written. Jesus predicted even further persecution, but told the believers not to fear. He promised a crown of life to them if they remained loyal to Him to the point of martyrdom. The church at Smyrna prefigures the history of the Church from the mid-third century to AD 316, when Emperor Constantine declared Christianity an official state religion. Out of seven churches mentioned in Revelation, Smyrna is one of only two not rebuked for any specific flaw.
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“Revelation 2:10” Bibleref.com
10 Don’t be afraid of the things which you are about to suffer. Behold, the devil is about to throw some of you into prison, that you may be tested; and you will have oppression for ten days. Be faithful to death, and I will give you the crown of life.