Why would the devil cast the Smyrna believers into prison?
The devil would cast some Smyrna believers into prison for their faith, so that they might be tried or tested. This testing brought tribulation, described as ten days, understood as ten distinct periods of Roman persecution. The believers endured because the Lord promised to be with them.
Les explains that the church of Smyrna was going through horrible pressure. They were poor materially because persecution took away their income, jobs, and wealth, but spiritually they were rich. The devil would cast some of them into prison for their faith, so they might be tried or tested, and they would have tribulation. Les interprets the ten days as ten distinct periods of time during the Roman Empire when the church came under horrible pressure. But these believers did not give up; they went through it because the Lord had promised to be with them. They were told to be faithful unto death, and they would receive a crown of life. Les also notes that believers will suffer tribulation, and that freedom of worship has been rare in history.
Fear none of those things which thou shalt suffer: behold, the devil shall cast some of you into prison, that ye may be tried; and ye shall have tribulation ten days: be thou faithful unto death, and I will give thee a crown of life.