“The adulterer, at the time he is committing adultery, is not
a
believer; (the wine drinker) at the time he is drinking, is not a
believer; the thief, at the time he is stealing, is not a believer;
the plunderer, at the time he is plundering with the people looking
on, is not a believer.”
Sunan Ibn Majah Book 36, Hadith 11