What is the meaning of hellfire-and-brimstone?

Answer 1

Hell fire means fire of the lake of fire and brimstone means the kind of stone in lava.

Another answer:

It is what God uses as a tool to destroy the wicked, just like He did with Sodom and Gomorrah. And it is what He will use to finally destroy the wicked in the lake of fire that Revelation talks about.

Some people believe that the lost will burn in this fire and brimstone for all eternity. But this is a false teaching and is not supported by The Bible.

The Bible teaches that we are made from the dust of the ground. And once we die, we return to dust (Genesis 3:19). So how can the lost who have turned to dust burn forever in hell fire? It's not possible. And if you look at the creation account, God made Adam from the dust of the ground and breathed into him the breath of life and Adam BECAME a living soul. Adam wasn't GIVEN a soul. So there is no "soul" left to burn in hell when we die.