So where does this fire come from?
At the end of the 1000 years (the millenium) of Revelation 20, the lost are resurrected. This is the resurrection of condemnation talked about by Jesus in John 5:28-29, NKJV: Do not marvel at this; for the hour is coming in which all who are in the graves will hear His voice and come forth -- those who have done good to the resurrection of life, and those who have done evil, to the resurrection of condemnation.
In this resurrection, Satan deceives the lost into thinking that with their vast numbers and genius they can take the Holy City through battle and claim it and its riches as their own. But as the armies march up around the city to begin the onslaught, and fire came down from God out of heaven and devoured them. Revelation 20:9, NKJV. And anyone not found written in the Book of Life was cast into the lake of fire. Revelation 20:15, NKJV. But the cowardly, unbelieving, abominable, murderers, sexually immoral, sorcerers, idolaters, and all liars shall have their part in the lake which burns with fire and brimstone, which is the second death. Revelation 21:8, NKJV.
God withdraws His sustaining power, the power that holds all things together, and that withdrawing causes sin and sinners to disintegrate. To allow them to live on in the misery, disease and torment of sin would be unthinkable to God's love. Out of mercy to them they will be destroyed by the second death. This is God's strange act (Isaiah 28:21). He does it because His universe is built on free choice. He will not force anyone to be saved.
What will happen after that?
Are you sure God can't save them?
If God is going to destroy sin and sinners eventually, why doesn't He do it now?
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