That the Bible speaks of hell is quite clear. What is meant by hell is not always so clear due to at least two things. One, several Greek words are translated into the one word hell (Hades, Tartarus, and Gehenna), as well as one Hebrew word (Sheol), which is the Hebrew equivalent of the Greek word Hades. Two, there is a false doctrine that demands that hell is not a literal place, but that it merely refers to the grave.
Let us clear up the first problem by identifying the different words translated as hell in English. As mentioned above, the words Hades and Sheol refer to the same thing, namely, the realm of the unseen. They are words that are often used in reference to the place where the spirit goes when the body dies. Sheol is used in reference to an unseen place in Jonah 2:2 (the belly of the big fish) and the place of departed spirits in Psalms 16:10. In the New Testament Hades is always used to denote the place of departed spirits. Neither of these words are ever used to refer to the common grave or tomb. More on that later.
Tartarus is also translated as hell in the Bible. It is found only in 2 Peter 2:4. The context of that chapter, especially verses 3, 4, 9, and 17, makes it clear that it is the place where wicked souls go after death to await eternal punishment. It seems to be equivalent to the place of torment in which the rich man found himself in Luke 16:23, 28.
Finally, there is Gehenna, and this is the place one thinks of most when considering hell. It is the place of eternal punishment where there shall be weeping and gnashing of teeth. The word is found in the following passages: Matthew 5:22, 29, 30; 10:28; 18:9; 23:15, 33; Mark 9:43, 45, 47; Luke 12:5; and James 3:6. It is clear from some of these passages that the inhabitants of this place will be conscious.
Now, to the second problem—hell being a reference to the common grave. That position is a conclusion reached by human reasoning. It is most commonly held by Jehovah’s Witnesses, but like much of their doctrine, it cannot be substantiated by the Bible. In Genesis 37:35 Jacob said, “…For I will go down to Sheol to my son mourning…” Jacob believed that his son, Joseph, was in Sheol. Did Jacob refer here to the grave? No! Remember, he thought Joseph had been eaten by a wild animal. He was referring to the place of departed spirits. As we have already seen, Sheol is not the final destination for man, heaven or hell (Gehenna) is, but it is clearly more than the common grave, at least Jacob believed it was. His view is corroborated by the use of Sheol regarding Jonah, as we observed above (Jonah 2:2).
Another truth that proves that hell is more than the grave is seen by the fact that there is a worse punishment for sin than death. The Hebrews writer affirmed that one who learns and obeys the truth, then turns away from it, will be punished more severely than the transgressor of Moses’ law (Hebrews 10:28, 29), which was death. How could this be so if the final punishment is merely death? Would that not, in the end, be the same punishment, not worse? Also, it is said of Judas that it would have been good for him if he had not been born, based upon his betrayal of Jesus (Matthew 26:24). But, if Judas did not exist before he was born, and at death, he goes back into non-existence, then how would it have been better for him not to have been born? There must be a fate worse than non-existence. That fate is eternal punishment in hell (Gehenna).
Do not be swayed by the false doctrine that says there is no hell, or that hell is just the grave. Live right before God, for if you do not, everlasting punishment will be the consequence.