Betting
Question :
What is the ruling on betting of some people which they claim to be right?
Answer:
Al-Murahanah according to many people; when two people agree that one of them has to pay the other if he is right, is unlawful, because it is a form of gambling which Allâh Almighty mentioned alongside alcohol:
"O you who believe! Intoxicants (all kinds of alcoholic drinks), gambling, Al-Ansab (stone altars), and Al-Azlam (arrows for seeking luck or decision) are an abomination of Shaytan's handiwork. So avoid that in order that you may be successful. Shaytan wants only to excite enmity and hatred between you with intoxicants (alcoholic drinks) and gambling, and hinder you from the remembrance of Allah and from As-Salat (the prayer). So, will you not then abstain?"
People simply become more reprehensible when they give their bad deed a good name, such as in this case: they call gambling "establishing the truth." They are not only performing a bad deed by gambling, but are also liars by claiming that it is something good.
We ask Allah to grant us safety and pardon.
Source:
Ibn 'Uthaimin
Fatawa Islamiyah, Vol. 8 Page 260