Sahih Bukhari | Volume 3 | Hadith Number 655

Narrated by Abu Huraira
The Prophet said, "When an adulterer commits illegal sexual intercourse, then he is not a believer at the time, he is doing it, and when a drinker of an alcoholic liquor drinks it, then he is not a believer at the time of drinking it, and when a thief steals, then he is not a believer at the time of stealing, and when a robber robs, and the people look at him, then he is not a believer at the time of doing robbery.