Read Leviticus 20:14 Using Other Translations
And if a man take a wife and her mother, it is wickedness: they shall be burnt with fire, both he and they; that there be no wickedness among you.
If a man takes a woman and her mother also, it is depravity; he and they shall be burned with fire, that there may be no depravity among you.
“If a man marries both a woman and her mother, he has committed a wicked act. The man and both women must be burned to death to wipe out such wickedness from among you.