عَنْ عُرْوَةَ عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ كَانَ إِذَا جَلَسَ مَجْلِسًا أَوْ صَلَّى تَكَلَّمَ بِكَلِمَاتٍ فَسَأَلَتْهُ عَائِشَةُ عَنِ الْكَلِمَاتِ فَقَالَ إِنْ تَكَلَّمَ بِخَيْرٍ كَانَ طَابِعًا عَلَيْهِنَّ إِلَى يَوْمِ الْقِيَامَةِ وَإِنْ تَكَلَّمَ بِغَيْرِ ذَلِكَ كَانَ كَفَّارَةً سُبْحَانَكَ وَبِحَمْدِكَ لَا إِلَهَ إِلَّا أَنْتَ أَسْتَغْفِرُكَ وَأَتُوبُ إِلَيْكَ
It is narrated from Sayyida Aisha (may Allah be pleased with her) that when the Messenger of Allah (peace and blessings be upon him) would sit in any gathering or perform prayer, he would say some supplicatory words. Sayyida asked him (peace and blessings be upon him) about these words. He (peace and blessings be upon him) said: If a person speaks good words, these words will be a seal upon them until the Day of Resurrection, and if he says anything other than good, these words will become an expiation for him. The words are: Subhanaka wa bihamdika la ilaha illa anta astaghfiruka wa atubu ilayk (Glory is to You and with Your praise, there is no true deity except You, I seek Your forgiveness and turn to You).