The Ruling on Playing Cards and Chess
Question :
Is it permissible to play chess? What about playing cards?
Answer:
There are statements from the scholars, may Allah have mercy upon them, that these are unlawful, and this has also been mentioned by our Shaykhs. They are unlawful because they deter people from remembering Allah Almighty and from praying, because they lead to ill will between the players, and because they are sometimes played for money, which is unlawful. The Shari'ah approves of playing for money in only three activities: archery, camel racing, and horse racing (and even that, under certain conditions).
When one observes those who play chess or cards, one quickly realizes that they are wasting their time gaining neither in rewards for worship nor in benefits of the worldly kind. Some people claim that chess and card playing open the mind and make one more intelligent, a claim that is false: in reality, these games make the mind dull or at the very most, intelligent in only these games, dull in other situations or activities.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 8 Pages 264-265