English Bibles often translate Gehenna simply as 'hell,' which can hide the geographical origin of Jesus' word. Gehenna derives from the Valley of Hinnom outside Jerusalem.
Its scriptural history made the name a powerful image of judgment for Jesus' Jewish hearers.
The Valley of Hinnom is associated in the Old Testament with abhorrent practices including child sacrifice, condemned by Israel's prophets and kings. Jeremiah uses the valley in prophetic announcements of judgment. In later Jewish usage, Gehenna developed beyond the literal valley into an image associated with divine punishment.
The popular claim that the valley functioned in Jesus' day as Jerusalem's continuously burning garbage dump is not securely established and should not be treated as the explanation of the term.
Recognizing the biblical geography gives Jesus' warnings their scriptural depth. Gehenna evokes a real place whose history had become associated with rebellion and judgment.
The term is therefore stronger than a generic word for something unpleasant, while its meaning should be derived from Jewish scriptural and judgment imagery rather than from unsupported stories about a municipal garbage fire.