If a man marries both a woman and her mother, it is depraved. Both he and they must be burned in the fire, so that there will be no depravity among you.
Jewish Publication Society of America Version (JPS1917) - Leviticus 20:14 >And if a man take with his wife also her mother, it is wickedness: they shall be burnt with fire, both he and they; that there be no wickedness among you.