God does not protect His faithful children from suffering. He knows that suffering is necessary for our spiritual growth. And the church in Smyrna was not spared suffering. But the Lord encouraged them saying, "Do not fear what you are about to suffer."(Rev.2:10). The Lord warned them that Satan was going to cast some of them into prison. God has given Satan the power to cast believers into prison unjustly. But we must remember that Satan can't do anything to us without first getting God's permission. And even if we are cast into prison, it will only be in order to test us (Rev.2:10). God uses even imprisonment to fulfil His purposes.
Paul said, "My circumstances (in prison) have turned out for the greater progress of the gospel" (Phil.1:12-14). God used Paul's imprisonment to fulfil a number of purposes: (i) to sanctify Paul; (ii) to convert a number of Paul's jailers; (iii) to give Paul an opportunity to write his epistles; and (iv) to encourage many other believers to preach fearlessly. Truly our God is able to turn the tables on Satan in such a way that everything (including imprisonment) works only for the fulfillment of the Divine purposes (Rom.8:28; Psa.76:10).
How long we spend in prison is also determined by the Lord. "You will have tribulation ten days", the Lord tells them (Rev.2:10). It is our Heavenly Father Who decides the length of time that His children have to undergo tribulation. Even in the days of the great tribulation, Jesus said that "for the sake of the elect those days shall be cut short." (Mt.24:22). "God remembered Noah" when the flood was on the earth (Gen.8:1). And He wont forget His elect when they are encompassed by the great tribulation on earth. "I will not forget you...I have inscribed you on the palms of My hands", is His Word to us (Isa.49:15,16).
It is a great comfort for us to know this. And we must remember it in the days to come, when we have to suffer for the Lord's sake. He will never allow us to be tested beyond our ability. He has His Hand on the control knob and He will turn down the pressure (that we are facing) when the right time comes. "Be faithful until death, and I will give you the crown of life", is the Lord's exhortation (Rev.2:10). We should be willing even to die if necessary, in order to stand true to the Lord. Don't follow the example of believers who compromise their witness just for the sake of a little earthly gain - some honour or promotion or money etc., How will such believers stand true to the Lord in the day when we wont be allowed to buy even our necessary food without the mark of the Antichrist (Rev.13:16,17)? Surely such "believers" will accept "the mark of the beast" in order to survive. Remember that the crown of life is a far greater reward than any earthly honour and even than physical life itself.
Again the Lord recognises that not all have ears to hear such a message. And so He calls those who have ears to hear, to hear. The overcomers will not be hurt by the second death (Rev .2:11). The second death is eternal death - being cast away from the presence of God for all eternity, into a lake of fire. It is significant that the promise of escaping the second death is made only to the overcomers. That's why it is so important to overcome sin - for death is the end- result of sin (as James 1:15 makes clear). The fundamental message of the Spirit throughout the New Testament is that we should overcome sin in every form.