Khulūd often denotes lasting or everlasting residence, but Arabic usage is also discussed in which related forms refer to a very long duration. The theologians examine the relevance of that lexical possibility.
One approach preserves the apparent permanence of a warning while identifying its subject as unbelievers or circumstances amounting to unbelief. Another considers whether extended duration is linguistically possible in a particular context.
It would be wrong to claim that khulūd always means only temporary residence. Its sense must be determined with context and the other evidence.