Abu Hurairah (RadiyAllahu Anhu) reported:

That the Messenger of Allah (صَلَّى اللّٰهُ عَلَيْهِ وَسَلَّمَ ) said:

“Whoever sits in a gathering and indulges in useless talk and before getting up supplicates:

“Subhanaka Allahumma wa bihamdika, ashhadu an la ilaha illa Anta, astaghfiruka wa atubu ilaika”

(O Allah, You are free from every imperfection; praise be to You. I testify that there is no true god except You; I ask Your Pardon and turn to You in repentance),

he will be forgiven for (the sins he may have intentionally or unintentionally committed) in that assembly.”