Albert Barnes Commentary Mark 9:44-46

"[where their worm dieth not, and the fire is not quenched.] And if thy foot cause thee to stumble, cut it off: it is good for thee to enter into life halt, rather than having thy two feet to be cast into hell. [where their worm dieth not, and the fire is not quenched.]" — Mark 9:44-46 (ASV)

Their worm. This figure is clearly taken from Isaiah 66:24. In describing the great prosperity of the kingdom of the Messiah, Isaiah says that the people of God will go forth and look upon the carcasses of men who have transgressed against God. Their enemies will be overcome.

They will be slain. The people of God will triumph. The figure is taken from heaps of the dead slain in battle; and the prophet says that the number will be so great that their worm—the worm feeding on the dead—will not die, but will live long, as long as there are carcasses to be devoured. He also says that the fire used to burn the bodies of the dead will continue to burn for a long time and will not be extinguished until they are consumed.

The figure, therefore, denotes great misery, and certain and terrible destruction. In these verses, it is applied to the state beyond the grave and is intended to denote that the destruction of the wicked will be awful, widespread, and eternal. It should not be supposed that there will be any real worm in hell—perhaps no material fire.

Nor can it be said what was particularly intended by the undying worm. There is no authority for applying it, as is often done, to remorse of conscience any more than to any other of the pains and reflections of hell. It is merely an image of loathsome, dreadful, and eternal sufferings.

In what that suffering will consist, it is probably beyond the power of any mortal to imagine. The word "their," in the phrase "their worm," is used merely to keep up the image or figure. Dead bodies, putrefying in that valley, would be overrun with worms, while the fire was not confined to them but spread to other objects, kindled by combustibles throughout all the valley. It is not meant, therefore, that every particular sufferer has a peculiar worm, or has particular sins that cause remorse of conscience. That is a truth, but it does not appear to be intended here.