The Lord describes the final destination of the wicked as a place of unquenchable fire. This place was created for the devil and his ministers, and also for the reprobate, who know not Christ.
The image of fire is continuously present in the Bible. It is associated with judgment and in the case of hell, it is also eternal.
Many religions try to downplay the fire of Hades, like those who want to preach that God is loving and will never send “good” people to hell. But the Bible is clear to point out the nature and manifestation of the “just judgment of God”.
When the Lord Jesus Christ described the eternal punishment of the reprobate, He said it was a place of darkness, and weeping and gnashing of teeth. He also added that its fire never quenched and its worm never died.
We read in the Revelation of Jesus Christ, which is the last book of the Bible, that the men that are punished by God clenched their teeth at Him because of their torment.
That is the key word: torment. There are several places where this torment is described. The rich man in Luke 16 was tormented in Hades. We also read in Revelation that the wicked, Satan and his ministers will be tormented in hell (lake of fire) forever and ever.
This final punishment is the manifestation of the just judgment of God: His justice and His glory. That is the unquenchable torment of fire. Contrary to those who preach annihilation, hell is forever and its fire shall never quench.