Chapter 46: The Book of Cutting off the Hand of the Thief
It was narrated from abu Hurairah that the Messenger of Allah said: "No one who commits Zina is a believer at the moment when he is committing Zina; no one who steals is a believe at the moment when he is stealing; no one who drinks wine is a believer at the moment when he is drinking it; and no robber is a believer at the moment when he is robbing and the people are looking on.
Sunan an-Nasa'i 4870