(They question thee about strong drink and games of chance…) [2:219].
This was revealed about 'Umar ibn al-Khattab, Mu'adh ibn Jabal and a group of Helpers who went to the Messenger of Allah, Allah bless him and give peace, and said: “Please give us your verdict about intoxicants and games of chance, for intoxicants suspend people's reasoning faculties while games of chance waste their money”. As a response, Allah, exalted is He, revealed this verse.
Asbab Al-Nuzul by Al-Wahidi , trans. Mokrane Guezzou