رَضِيتُ بِاللَّهِ رَبًّا، وَبِالْإِسْلَامِ دِينًا، وَبِمُحَمَّدٍ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ نَبِيًّا
Transliteration
Raditu billahi Rabba, wa bil-Islami dina, wa bi-Muhammadin sallallahu 'alayhi wa sallama nabiyya
Translation
I am pleased with Allah as my Lord, with Islam as my religion, and with Muhammad (peace be upon him) as my Prophet.
Reference: Abu Dawud 5072