سُبْحَانَكَ اللَّهُمَّ وَبِحَمْدِكَ، أَشْهَدُ أَنْ لَا إِلَهَ إِلَّا أَنْتَ، أَسْتَغْفِرُكَ وَأَتُوبُ إِلَيْكَ
How perfect You are O Allāh, and I praise You. I bear witness that None has the right to be worshiped except You. I seek Your forgiveness and turn to You in repentance.
Reference: How perfect You are O Allāh, and I praise You. I bear witness that None has the right to be worshiped except You. I seek Your forgiveness and turn to You in repentance. Abū Dāwud (#4859), al-Tirmidhī (#3433), and al-Nasāʾī in _ʿAmal al-Yawm wa al-Laylah_ (#397). Also see _Ṣaḥīḥ al-Tirmidhī_ (3/153).