In referencing hellfire, what did Jesus mean by “their worm does not die?”
Let’s look at the text this phrase comes from:
“And if your eye causes you to sin, pluck it out. It is better for you to enter the kingdom of God with one eye, rather than having two eyes, to be cast into hell fire—where ‘Their worm does not die and the fire is not quenched.’” Mark 9:47–48
Jesus often used metaphors and illustrations to communicate the likeness and reality of Heaven and the realities of the will of God—and this passage is no different. The word for hell here in the original Greek is Gehenna. This was a region in the valley of Hinnom outside of Jerusalem. Gehenna was a giant city dump or landfill in which animal carcasses and rubbish were disposed of. What was not destroyed by the smoldering fires was eaten and consumed by worms and maggots. So basically, Christ is using Gehenna as a metaphor for hellfire at the end of the world (see Matthew 13:40). Gehenna is a representation of the destructive lake of fire at the end of time (see Revelation 20:9–10).
Don’t get too caught up on the worm not dying. This is metaphorical language describing the everlasting results of hellfire, not the burning itself. In fact, we know this is figurative language because worms cannot feast on disembodied souls, according to the popular but erroneous belief in the immortality of the soul. In contrast, the Bible makes it clear that the wicked enter hellfire with their whole body (emphasis supplied):
“And if your right hand causes you to sin, cut it off and cast it from you; for it is more profitable for you that one of your members perish, than for your whole body to be cast into hell.” Matthew 5:30
“Where their worm does not die” is allegorical language describing the eternal and everlasting results of hellfire. Notice how Jesus also says in verse 48, “…and the fire is not quenched.” This refers to the fact that no one can put out the fires of hell until it has served its purpose in eradicating sin. Even Malachi saw that the wicked would be reduced to ashes (see Malachi 4:3), so we know that the fires will only go out after sin has been completely destroyed—and not a moment before.
Therefore, “where their worm does not die” is allegory, communicating the eternality of the results of the destruction of the wicked.