John Calvin Commentary Isaiah 66:24

"And they shall go forth, and look upon the dead bodies of the men that have transgressed against me: for their worm shall not die, neither shall their fire be quenched; and they shall be an abhorring unto all flesh." — Isaiah 66:24 (ASV)

And they shall go forth. We must not attempt here to obtain subtle and ingenious interpretations, for he simply informs those who will be adopted into the Church that they will see, all around them, the dreadful vengeance of God. Yet there is an implied contrast between the severity of the calamity and the free departure, as if he had said, “Out of the dark prison in which they had been confined they will again come forth to the light.”

And shall see the dead bodies of men. He does not mean that this slaughter will take place in the assembly of believers, for this would greatly diminish the happiness of the Church, in which God displays all testimonies of joy and gladness. But as he previously spoke of the perpetual glory by which He will dignify His people, so he now threatens the punishment which He will inflict on the reprobate, so that the godly may be more careful to keep themselves in the fear of God.

And their fire shall not be extinguished. When he says that they will be tormented by “fire,” this mode of expression, as I have previously remarked, is metaphorical. This is clearly evident from the following clause, for worms will not be formed out of the earth to gnaw the hearts of unbelievers.

The plain meaning, therefore, is that the wicked will have a bad conscience as an executioner, to torment them without end, and that torment awaits them greater than all other torments. Finally, they will tremble and be agitated in a dreadful and shocking manner, as if a worm were gnawing a man's heart, or a fire were consuming it, and yet, though thus consumed, he did not die.

And they shall be an abhorrence to all flesh. Because the wicked are now held in the highest honor, and from their lofty position look down with contempt on good men, the Prophet threatens a shocking change; for, along with unutterable torments, they will also endure the deepest disgrace; as it is just and right that those who despised and reproached the glory of God will be loaded with every reproach and will be the objects of abhorrence to angels and to the whole world.