Gehenna, from the Greeh geenna or the Hebrew hinnom, the Valley of Hinnom, is a deep narrow glen south of Jerusalem, where the Jews offered their children to the god Molech (2 Kings 23:10; Jeremiah 7:31, 19:2-5), as seen in Jeremiah this practice was strongly condemned by the prophets. Later it became a refuge for all putrefying material which defiled the city; and thus became a symbol of the place of everlasting punishment, especially with its accounts of eternal burning fire to which Christ referred to when he said, “the fire is not quenched.”
According to New Testament accounts Christ and the apostles used the expression of “gehnna” often, denoting its common usage at the time, signifying this was a place for the lost or unsaved. Christ mentions Gehenna several times as a consequence of sin; he describes it as a place where their worm never dies, and their fire is never to be quenched. Gehenna is identical in meaning to the “lake of fire” (Revelation 19:20, 20:10, 14, 15). Moreover the “second death” and “lake of fire” are identical terms (Revelation 20:14). These latter scriptural expressions described the eternal state of the wicked as forever separated from God and consigned to the abode of unrepentant angels and men. Gehenna, as Biblically described, is a permanent, eternal place of punishment in which the unfaithful and wicked reside forever and is not to be confused with Hades or Sheol. The distinction between Gehenna (an eternal state) and Hades and Sheol (intermediate states) is important in Christian theology especially concerning Christ’s descent into hell; according to Christian theology Christ descended into Hades, an intermediate state.The Persian view of Gehenna also describes it as a place inhabited by divs, or rebellious angels, because they refused to bow to the first man. A.G.H.
Unger, Merrill F., Unger’s Bible Dictionary, Chicago, Moody Press, 1966, pp. 394-395, 467
Bowker, John, The Oxford Dictionary of World Religions, New York, Oxford University Press, 1997, p. 369
Spence, Lewis, An Encyclopedia of Occultism, New York, Carol Publishing Group Edition, 1996, p. 177