Genesis 19:26 is famously brief. Targum Pseudo-Jonathan is not.

"And his wife looked after the angel, to know what would be in the end of her father's house, for she was of the daughters of the Sedomaee; and because she sinned by salt (bemilcha) she was manifestly punished; behold, she was made a statue of salt."

The Targum adds two crucial details the Hebrew leaves out. First, Lot's wife is Sodomite by birth. Her family — her father's house — is still inside the burning plain. Her backward glance is not mere curiosity. It is divided loyalty. She cannot bear to let go of her people of origin, even when God has declared them finished.

Second, and more striking: the Targum tells us the specific sin she committed that earned the specific punishment. She sinned "by salt" — bemilcha. The rabbinic tradition preserved here (also found in Bereshit Rabbah 50:4 and Pirkei DeRabbi Eliezer 25) explains: when the angels arrived and Lot asked his wife to prepare food for them, she went around the city borrowing salt from the neighbors, deliberately advertising the fact that her household was entertaining strangers. She was, in effect, reporting her husband to Sodom's anti-hospitality police.

Salt was her weapon. Salt became her sentence. Middah k'neged middah — measure for measure — in its purest form.

The takeaway: a person who cannot let go of the community that destroys kindness will, eventually, be preserved as a monument to the thing they could not leave.