It is narrated from Sayyiduna Ibn Abbas, Sayyiduna Ibn Umar and Sayyiduna Abu Hurayrah (may Allah be pleased with them) that the Prophet (peace and blessings be upon him) said: "The adulterer does not remain a believer when he commits adultery; the drinker does not remain a believer when he drinks wine; the thief does not remain a believer when he steals; and no one remains a believer while he is plundering something valuable."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13247