رَضِيْتُ بِاللهِ رَبًّا، وَبِالإسْلامِ دِيْناً، وَبِمُحَمَّدٍ نَبِيًّا [ثَلاثَ مَرَّاتٍ]
I am pleased with Allāh as the Lord, and Islam as the religion and Muḥammad as the Prophet.
Reference: I am pleased with Allāh as the Lord, and Islam as the religion and Muḥammad as the Prophet. Aḥmad (4/337), al-Nasāʾī in _ʿAmal al-Yawm wa al-Laylah_ (#4), Ibn al-Sunnī (#68), Abū Dāwud (#5072, 4/318), and al-Tirmidhī (#3389, 5/465). Shaykh Ibn Bāz declared it ḥasan in _Tuḥfah al-Akhyār_ (#39).