Why is salt introduced here?

Meyer¹ thinks of the salt on the sacrifices: covenantal salt, but then in this case covenantal wrath. Gould² rightly points out that in the whole of verse 50, Meyer gives two meanings to “salt” (“covenantal wrath” and “covenantal wisdom”). He himself thinks of the purifying work (if one is not purified/salted by cutting off his own limbs then this is done by the Gehenna-fire). This explanation fails to do justice, however, to the everlasting character of Gehenna (“The fire is not quenched”). This suggests that “being salted” must be of a negative character, and endlessly so. One could think of Sodom and Gomorrah. By the fire of God’s judgment Lot’s wife became a pillar of salt and the regions of Sodom and Gomorrah have become a lasting Salt Sea. Nothing is more final than the infertility of this area, and this is the result of God’s judgment of fire. Verse 50a then means, “Thus one is forever eliminated, for fire will change everyone into infertile salt, as happened with Sodom, Gomorrah, and Lot’s wife.” (For an explicit reminder of Lot’s wife, see Luke 17:29–32.)³