The Messenger of Allah ﷺ said, "Prompt your dying ones to say, 'There is no god but Allah.'"
قال رسول الله ﷺ: لقنوا موتاكم لا إله إلا الله.
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Muslim narrated it in the Book of Funerals (917) through several chains, from Abu Khalid Ahmar, from Yazid bin Kaysan, from Abu Hazim, from Abu Hurairah, and he related the hadith. Ibn Hibban also narrated it in his Sahih (3004) through another route, from Abu Hurairah, who said, the Messenger of Allah ﷺ said, "Prompt your dying with, 'There is no god but Allah,' for whoever's last words at death are, 'There is no god but Allah,' will enter paradise at some point, even if he was afflicted before that by whatever afflicted him." Its chain is sahih. It has also been related from him as a stopped narration, but the raised version is more correct.