Where their worm does not die, and the fire is not quenched.
The repetition has an instructive purpose. When the same warning is sounded again, the Lord shows that this is not a secondary theme. A person is inclined to forget or downplay the danger of sin, and for this reason the image of judgment is brought forward again. The images of the unquenchable fire and the worm that does not die are heavy for our senses, but they are given to awaken the soul, so that a person may decisively turn away from everything that leads him to destruction..