´It was narrated that Abu Hurairah said:` "The Messenger of Allah [SAW] said: 'The adulterer is not a believer at the moment when he is committing adultery, and the wine drinker is not a believer at the moment when he is drinking wine, and the thief is not a believer at the moment when he is stealing, and the robber is not a believer at the moment when he is robbing and people are looking on.'"
Explanation & Benefits
Hafiz Muhammad Ameen
(1) The purpose of the hadith is that these actions are contrary to faith (iman). Faith does not tolerate these actions; rather, it prevents them. This does not mean that one becomes a disbeliever (kafir), because no major sin (kabirah) makes a Muslim a disbeliever. For details, see Hadith: 4873.
(2) From this narration, it is established that drinking alcohol (khamr) is a major sin (kabirah), because it has been described as contrary to faith. In any case, drinking alcohol necessitates the prescribed punishment (hadd), and any act that incurs a hadd is certainly a major sin. Just as adultery (zina), theft (sariqah), and highway robbery (qat‘ al-tariq) are included among the major sins, likewise, drinking alcohol is also a major sin.
(3) “They keep watching” means that due to helplessness, they are unable to confront (the wrongdoer).
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 5662