"O ye who believe! wine and the game of chance... are only an abomination of Satan's handiwork. So shun each one of them that you may prosper. Satan seeks only to create enmity and hatred among you by means of wine and games of chance, and to keep you back from the remembrance of Allah and from Prayer..." (5:91-92)
The Arabic word "al-khamr" is used in this verse which means anything that intoxicates or alters the mind. Thus, all forms of intoxicants are forbidden. The verse clearly explains the problems created by the use of intoxicants; first, they lead to hatred and enmity amongst people, causing murder, violence, immoral behavior etc.; and secondly they lead people away from Allah and His religion. Allah wants the believers to keep their minds pure and clean, so that they worship Him fully. A Muslim may not offer prayers (salaat) when he is not in full possession of his senses, even if that is caused by excessive emotion or a state of sleep. Certainly, a mind that is intoxicated is not able to focus on Allah.