Charles Ellicott Commentary Genesis 19:26

"But his wife looked back from behind him, and she became a pillar of salt." — Genesis 19:26 (ASV)

His wife looked back from behind him. — In Eastern countries, it is still the rule for the wife to walk behind her husband. Regarding the method of her transformation, some think that she was stifled by sulfurous vapors and her body subsequently encrusted with salt.

More probably, the earthquake heaped up a mighty mass of the rock-salt, which lies in solid strata around the Dead Sea, and Lot’s wife was entangled in the convulsion and perished, leaving the hill of salt in which she was enclosed as her memorial.

Salt cones are not uncommon in this neighborhood. The American Expedition found one, about forty feet high, near Usdum (Lynch, Report, pages 183 and following).

Entombed in this salt pillar, she became a monument of an unbelieving soul .