The Greek word GeHenna is often translated as Hell Fire in other Bibles.
However, the word simply means the Valley (heb. ge) of Hinnom.
Understand that the Valley of Hinnom (also referred to as ‘the Valley of the Sons of Hinnom‘) was an actual place in ancient JeruSalem.
It wasn’t some symbolic Hell fire;
Rather, it was a valley that was used as the city’s garbage dump, which was located along the southeastern corner of its outer wall.
Before JeruSalem’s conquest by Babylon, the Valley of Hinnom had once been a beautiful park.
However, because unfaithful Jews started offering their children as sacrifices on an altar to the God Moloch there (see 2 Chronicles 28:3); After their repatriation to JeruSalem, the people started using it as a place to dump their garbage and refuse.
Of course, since it was a garbage dump, it was necessary to keep the garbage burning in order to reduce the stench and to limit the number of flies and rats. So, sulfur and sulfurous rocks know as ‘brimstone’ were regularly thrown into the dump to keep the fires burning hot.
And this is why Jesus, when using the term, spoke of the fire as not being put out.
Also, because worms (maggots) bred along the edges of the dump, he could say that the worms would always be there.
The only cases where humans were actually thrown into GeHenna provides an insight into what Jesus was talking about when he referred to people as going there. For there were cases where the dead bodies of particularly vile criminals were thrown into GeHenna’s fires, because people felt that they were undeserving of a decent burial. And as you read the Scriptures, you will notice the importance that Hebrews placed on being ‘laid to rest with their ancestors.’
So when Jesus spoke of people being thrown into GeHenna;
He was using the name of a familiar place to make the point that those whom God views as being unrepentant sinners would be thrown into the ‘garbage dump;’
For they were unworthy of a resurrection by Him.
Notice that this outcome was well illustrated by what happened to wicked Queen JezeBel, for her body was eaten by dogs.
Such an outcome for the willfully wicked was also referred to by Jesus (in Matthew’s account) as the fire of the age.
Why did he use that term?
Because fire destroys, and this destruction is for the ages.
(For more information, see the linked document, ‘Is there a Burning Hell?’)