Commentary for Genesis 19:26

ותבט אשתו מאחריו AND HIS WIFE LOOKED BACK FROM BEHIND HIM —behind Lot.

AND HIS WIFE LOOKED BACK FROM BEHIND HIM. From behind Lot, who was following them, acting as the rearguard for all his household, who were hurrying to be saved.

ותבט אשתו מאחריו, Lot’s wife who had been walking behind him turned around, seeing that she had little faith in such miracles as she had been warned would occur; This, in spite of the fact that she had personally overheard the angel warning Lot that no one was to turn around on pain of their becoming a victim of this destruction. Even though salt has not been mentioned as having been part of the lethal rain, the Torah speaking of sulfur and fire, it appears that the people themselves were turned into pillars composed partly of sulfur and partly of salt. We have proof of this in Deut. 29,22 when Moses describes the valley as it appeared in his time. The Israelites had not yet seen it, never having set foot in the land of Canaan as yet.