What should a married man do about his wife and her sister uttering obscenities, backbiting, and speaking obscenely about his mother and sister?

The wife should be guided through advice and dialogue, reminding her that good character elevates the status of a Muslim woman, and that the Prophet, peace be upon him, said: «NOTHING IS HEAVIER IN THE SCALES OF A BELIEVER ON THE DAY OF JUDGEMENT THAN GOOD CHARACTER, AND ALLAH DETESTS THE INDECENT, FOUL-MOUTHED PERSON». And that indecency in speech violates Allah's commands and is a form of disobedience, and that Allah commanded kindness in speech: ﴿AND TELL MY SERVANTS TO SAY THAT WHICH IS BEST﴾, and ﴿AND SPEAK TO PEOPLE GOOD WORDS﴾.

As stated in the hadiths: «WHOEVER BELIEVES IN ALLAH AND THE LAST DAY SHOULD SAY GOOD OR REMAIN SILENT», and «WILL PEOPLE BE THROWN ON THEIR FACES OR ON THEIR NOSES INTO HELLFIRE EXCEPT FOR THE HARVESTS OF THEIR TONGUES?». And that «MODESTY IS PART OF FAITH, AND FAITH IS IN PARADISE, AND INDECENCY IS FROM HARSHNESS, AND HARSHNESS IS IN HELLFIRE». Emphasize the seriousness of backbiting and that it is one of the major sins.

Regarding the husband's mother, the wife must be reminded of the obligation to respect and venerate her due to her old age, and that «HE IS NOT OF US WHO DOES NOT HAVE MERCY ON OUR YOUNG AND RESPECT OUR ELDERS», and «INDEED, AMONG THE GLORIFICATION OF ALLAH IS HONORING A MUSLIM ELDERLY PERSON».

Disciplining and advising the wife is part of the husband's guardianship and care, and this requires patience and gentleness. If direct advice does not work, a wise person from her family can be approached. And supplicating for her guidance should not be overlooked.