Albert Barnes Commentary Job 18:15

"There shall dwell in his tent that which is none of his: Brimstone shall be scattered upon his habitation." — Job 18:15 (ASV)

It shall dwell in his tabernacle - It is uncertain what this refers to. Some suppose that the implied word is “soul,” and that the meaning is, “his soul,” that is, he himself, “shall dwell in his tent.” Rosenmuller, Noyes, Wemyss, and others, suppose that the word is “terror.” “Terror (בלהה ballâhâh) shall dwell in his tent,” the same word that is used in the plural in the previous verse. This is undoubtedly the correct sense, and the idea is that his forsaken tent will be a place of terror—somewhat, perhaps, as we speak of a forsaken house as “haunted.” It may be that Bildad refers to the kind of superstitious fear that we sometimes, and almost always in childhood, associate with the idea of a house where no one lives.

Because it is none of his - It is no longer his. It is a forsaken, tenantless dwelling.

Brimstone shall be scattered - Brimstone has always been the image of desolation. Nothing will grow on a field that is covered with sulfur, and the meaning here is that his house would be utterly desolate and forsaken.

Rosenmuller and Noyes suppose that there is an allusion here to a sudden destruction, such as that of Sodom and Gomorrah. Grotius doubts whether it refers to that or to lightning. Others suppose that lightning is referred to both here and in Genesis 19:24 and Deuteronomy 29:23.

However, I can see no evidence here that there is any reference to Sodom and Gomorrah, or any allusion to lightning. If the allusion had been to Sodom, it would have been more detailed. That was a case “just in point” for the argument. The fact that it was so exactly relevant, and would have furnished Job’s friends with such irrefutable proof for the position they were defending, yet is not woven into the very texture of their argument, is, in my opinion, conclusive proof that this remarkable event is not referred to here.

The only thing necessarily implied in this language is that sulfur, the emblem of desolation, would be scattered on his dwelling, and that his dwelling would be completely desolate.