Matthew 10:28

And be not afraid of them that kill the body, but are not able to kill the soul: but rather fear him who is able to destroy both soul and body in hell.

Tertullian wrote of this:

Here we have a recognition of the natural immortality of the soul, which cannot be killed by men; and of the mortality of the body which may be killed: whence we learn that the resurrection of the dead is a resurrection of the flesh; for, unless it were raised again, it would be impossible for the flesh to be "killed in hell."[10]

The question of hell, that is, "Gehenna," will be examined more fully under Matthew 25:41, which see. Suffice it here to note that Gehenna, or the Valley of Hinnon, was used by Christ as a metaphor to describe the place of eternal punishment of the wicked. Whatever metaphor was employed, Christ left no doubt of the reality and dreadful nature of that punishment.