The word for "hell" in this verse is gehenna, and this is the only one of its eleven occurrences in the New Testament that is not a direct quote from the lips of Christ. Since the tongue is not a literal fire and since its misuse can in effect make it a "world of iniquity," this passage suggests that hell itself is the ultimate world of iniquity which has made the uncontrolled tongue an extension of itself.
The Bible speaks of this future hell as a place of "everlasting fire, prepared for the devil and his angels" (Matthew 25:41). However, if these were fires such as we have here on earth, it is difficult to see how, as Jesus said, God will "destroy both soul and body in hell" (Matthew 10:28). Fire would destroy the body, but what about the soul?
The fire of hell may include some kind of spiritual fire or environment whose destructive nature can only be characterized by the metaphor of fire. The "lake of fire" cannot be on earth, of course, because the Beast, the False Prophet, and Satan will all be sent there before the disintegration of earth in its present form, whereas all lost human souls will be sent there after that event (Revelation 19:20; 20:10-11, 15). The awful lake probably is somewhere far out in the "outer darkness" (Matthew 25:30; Jude 13).
And it will be "a world of iniquity" where "he that is unjust |will| be unjust still: and he which is filthy |will| be filthy still" (Revelation 22:11). Those who have opted not to be with Christ will be given their chosen status forever. That means no light, no peace, no rest, no joy, nothing at all associated with the Lord. One should certainly "flee from the wrath to come" (Matthew 3:7) while he can. HMM