Do not fear what you are about to suffer. Behold, the devil is about to throw some of you into prison to test you, and you will suffer tribulation for ten days. Be faithful even unto death, and I will give you the crown of life.
They are told not to fear the coming test but to remain faithful even unto death for the crown of life.
This verse gives the church its central command in the face of imminent suffering.
8To the angel of the church in Smyrna write: 9I know your affliction and your poverty — though you are rich! And I am aware of the slander of those who falsely claim to be Jews, but are in fact a synagogue of Satan. 10Do not fear what you are about to suffer. Behold, the devil is about to throw some of you into prison to test you, and you will suffer tribulation for ten days. Be faithful even unto death, and I will give you the crown of life. 11He who has an ear, let him hear what the Spirit says to the churches. The one who overcomes will not be harmed by the second death.