Traditions inform us that a respected person complained to
Hazrat Ilyas (a.s.) and Hazrat Khizr (a.s.) that people were
doing too much back biting and through this action they were
involved in a greater sin. How much ever I advise them to
prevent them from this, they do not pay attention to my advice.
Hazrat Ilyas (a.s.) said that there is only one way to prevent
this. You advise your people that whenever they enter a
gathering they should recite – Bismillahir Rahman Nir Raheem
Wa Sallallaho Ala Mohammadin Wa Aale Mohammad. When
they do that, Allah appoints an angel for that gathering who
prevents people from gheebat and also prays to Allah to grant
people the tawfeeq to avoid this sin.
Then Hazrat Khizr (a.s.) added, whenever you leave a
gathering then recite – Bismillahir Ramhan Nir Raheem Wa
Sallallaho Ala Mohammadin Wa Aale Mohammad. When you
do that, Allah appoints an angel in the gathering who prevents
the people from doing your gheebat
Ref : Fazila e Salawaat