"Two will never be gathered together in the Fire: A Muslim who killed a disbeliever then tried his best and did not deviate. And two will never be gathered together in the lungs of a believer: Dust in the cause of Allah, and the odor of Hell. And two will never be gathered in the heart of a salve: Faith and envy."
Sunan an-Nasa'i Book 25, Hadith 25