DHK said:
The cities were destoyed--that is the structures were burned up.
The cities were condemned--that is the people faced eternal destruction or punishment in hell. This is the only possible meaning when you take the two verses together.
This is true only to the extent that you bring the following view
to the Jude text: "eternal fire"
has to mean a fire that never will be extinguished and which will contain non-perishing human persons". This is a possible reading, of course, but on balance I think the evidence suggests otherwise.
First, the fact that the fire is described as "eternal" is not a warrant to conclude that there are people in that fire who, against the normal effects of fire, are not actually destroyed, but persist forever. This is a very unconventional way for fire to behave.
Second, there are Biblical precedents for use of references to "eternality" in an exaggerated form. There is a text in Samuel where a person is described as living in a certain earth-bound place "forever". Clearly, this is a poetic use of "forever". There is also the prediction by Isaiah about the destruction of Edom, where smoke is described as "rising forever" from Edom. I understand that Edom was indeed destroyed after Isaiah wrote these words. Yet no smoke rises from Edom today.
Third, it ignores the rather clear identification of a fire that reduces things to ashes (from teh 2 Peter text) with the "eternal" fire from Jude 7.
Fourth, it forces a re-intepretation of many Bibical texts from both testaments that state that the unredeemed are ultimately destroyed.
On balance, I think the above arguments are more powerful than the argument that "eternal fire" from Jude 7 refers to the never-ending torment to be endured by the residents of S&G.