"رَضِيتُ باللهِ رَبَّاً، وَبِالْإِسْلَامِ دِيناً، وَبِمُحَمَّدٍ صَلَى اللهُ عَلِيهِ وَسَلَّمَ نَبِيَّاً".

Radheetu billaahi Rabban, wa bil-'Islaami deenan, wa bi-Muhammadin (sallallaahu 'alayhi wa sallama) Nabiyyan.

I am pleased with Allah as my Lord, with Islam as my religion and with Muhammad (peace and blessings of Allah be upon him) as my Prophet. (Recite three times in Arabic .)

Reference

( Fortress of the Muslim: Invocations from the Qur'aan and Sunnah)
"Allah has promised that anyone who says this three times every morning or evening will be pleased on the Day of Resurrection."

Ahmad 4/ 337, An-Nasa'i, 'Amalul-Yawm wal-Laylah p. 4, Ibn As-Sunni (no. 68), At-Tirmithi 5/465. Its chain of transmission is good (Hasan), Ibn Baz, p. 39.

Note: By morning it refers to after Fajr until about ten minutes before duhr and by evening, one may read it after 'asr ( according to some scholars) or maghrib ( according to other scholars).

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