Sahih Muslim
The Book of Faith (Kitab Al-Iman)
Book Number: 001 / Hadith Number: 109
It is narrated on the authority of Abu Huraira: A fornicator who fornicates is not a believer as long as he commits fornication, and no one who steals is a believer as long as he commits theft, and no one who drinks wine is a believer as long as he drinks it, and repentance may be accepted after that.