Hisn al-Muslim · Book 1 · Hadith 153
من كان آخر كلامه "لا إله إلا الله" دخل الجنة
Lā ilāha illallāh Whoever dies with the last words (whose meaning is): "There is none worthy of worship but Allah" will enter Paradise. Reference: Abu Dawud 3/190. See also Al-Albani, Sahihul-Jami' As-Saghir 5/432.