Hadith 4:92
Abu Sa'id and Abu Huraira reported God's messenger as saying, “Recite to those of you who are dying, ‘There is no god but God. ’ ” Muslim transmitted it.
عَنْ أَبِي سَعِيدٍ وَأَبِي هُرَيْرَةَ قَالَا: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «لَقِّنُوا مَوْتَاكُمْ لَا إِلَهَ إِلَّا اللَّهُ» . رَوَاهُ مُسْلِمٌ
Original Reference: Mishkat al-Masabih 1616