Sunan An-Nasa'i
Hadith #4872
It was narrated that Abu Hurairah said:""No one who commits Zina is a believer at the moment when he is committing Zina; no one who steals is a believer at the moment when he is stealing; no one who drinks wine is a believer at the moment when he is drinking it."" - And he mentioned a fourth but I (the narrator) have forgotten it - ""When he does that the yoke of Islam is shed from his neck, but if he repents, Allah accepts his repentance