اَللَّهُمَّ إِنَّكَ قُلْتَ : اُدْعُوْنِيْ أَسْتَجِبْ لَكُمْ، وَإِنَّكَ لَا تُخْلِفُ الْمِيعَادَ، وَإِنِّيْ أَسْأَلُكَ كَمَا هَدَيْتَنِيْ لِلْإِسْلَامِ أَنْ لَّا تَنْزِعَهُ مِنِّيْ حَتّٰى تَتَوَفَّانِيْ وَأَنَا مُسْلِمٌ

Allaahumma innaka qulta: ud’uni astajib lakum, wa ainnaka laa tukhliful miyaada, wa inni as’aluka kamaa hadaytani leel-islaami an’laa tanzi’ahu minni hatta tatawaffaani wa annaa muslimun.

O Allah, surely you have said, pray to Me, I will answer your prayers. Surely you do not break the promise. I pray to you, do not deprive me of the way you have given me Islam (and the blessings of faith). Finally, let me die on Islam.

Reference: Zayyid Sanad (Muhammad ibn Abdil Wahhab). Al-Hadith Libni Abdil Wahhab 3/145