But He was speaking in plain language and not parables when warning of being cast into the lake of fire in eternal punishment.
I would think I would be burned up rather quickly. Especially if they said the fire was unquenchable and I was aware that often when bodies were burned in my culture the body was not completely consumed because the body itself put out the fire.
And since Jesus talked of the wheat and tares and the tares being burned up in other passages (and in my plain language the analogy clearly means destroyed as most people mean it), that would add to my being convinced that being thrown into the lake of fire was like being dried grass thrown into a furnace. It is utter destruction, with only CO2 blowing in the wind.
If the Lord told a story of a man who died and was in torments in Hell (Lk. 16:19-33) - and which would be science fiction if annihilationism is true, but which the Lord never used - and warned me it would be better off to pluck my eye out rather than to go to a place where their worm dieth not, and the fire is not quenched, (Mk. 9:43-48) into the furnace of fire where they would be weeping, wailing and gnashing of teeth, (Mt. 8:12; 13:42,50) and be cast into everlasting punishment in the same place the devil would, who will be tormented day and night forever, (Mt. 25:41,46; 20:10) and be tormented and with the smoke of my everlasting torment going up forever, Rv. 14:10,11) then i would believe that He wanted me to understand this as eternal torment. Simple as that.
And since Jesus talked of the wheat and tares and the tares being burned up in other passages (and in my plain language the analogy clearly means destroyed as most people mean it),
Luke has it, "Whose fan is in his hand, and he will throughly purge his floor, and will gather the wheat into his garner; but the chaff he will burn with fire unquenchable." (Luke 3:17)
The word "up" is not there in Mt. 3:12 either, and while katakaiō, for "burned" normally conveys burned up, yet just as the wicked, "shall be punished with everlasting destruction from the presence of the Lord, and from the glory of his power," (2 Thessalonians 1:9) for spiritual things are not destroyed, so this can denote ongoing destruction. The fact is that their fire is not being quenched, as it has an ongoing purpose, and that transgressors and of the sinners "shall both burn together, and none shall quench." (Is. 1:28,31; 66:24)
Moreover, the smoke of their torment does not cease, indicating ongoing destruction, for the laws of physics do not apply in the spiritual realm.