عَنْ أَبِي بَرْزَةَ الْأَسْلَمِيِّ رَضِيَ اللَّهُ عَنْهُ قَالَ كَانَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ بِآخِرَةٍ إِذَا طَالَ الْمَجْلِسُ فَقَامَ قَالَ سُبْحَانَكَ اللَّهُمَّ وَبِحَمْدِكَ أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا أَنْتَ أَسْتَغْفِرُكَ وَأَتُوبُ إِلَيْكَ فَقَالَ لَهُ بَعْضُنَا إِنَّ هَذَا قَوْلٌ مَا كُنَّا نَسْمَعُهُ مِنْكَ فِيمَا خَلَا فَقَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ هَذَا كَفَّارَةُ مَا يَكُونُ فِي الْمَجْلِسِ
It is narrated from Sayyiduna Abu Barzah Aslami (may Allah be pleased with him) that in the last part of the life of the Noble Prophet (peace and blessings be upon him), when a gathering would become lengthy, upon rising from it, he (peace and blessings be upon him) would recite this supplication: "Subhanaka Allahumma wa bihamdika, ash-hadu an la ilaha illa anta, astaghfiruka wa atubu ilayk" (Glory is to You, O Allah, and with Your praise; I bear witness that there is no deity except You; I seek Your forgiveness and turn to You in repentance). One of us said: Previously, we did not hear such supplicatory words from you, O Messenger of Allah (peace and blessings be upon him). He (peace and blessings be upon him) replied: These words are an expiation for the sins committed in the gathering.