The Messenger of Allah ﷺ said, "A disbeliever and the one who killed him will never be gathered together in the Fire."
حدثنا محمد بن الصباح البزاز حدثنا إسمعيل يعني ابن جعفر عن العلاء عن أبيه
قال رسول الله ﷺ لا يجتمع في النار كافر وقاتله أبدا
Muslim narrated it in the Book of Leadership, chapter "One who kills a disbeliever then remains steadfast," hadith no. 1891, from the hadith of Ismail bin Jafar, through this same chain.