Their argument is this: whenever only one of the two contestants puts up the stake, he is not genuinely content to be defeated and see his property taken. If he does lose, the victor consumes his wealth without his willing consent, though the Prophet ﷺ said, “The property of a Muslim is unlawful unless he freely agrees to give it.” (1)
That is unlike the case in which the prize is offered by the ruler or by someone unconnected to either racer, for such a donor willingly gives his money to whoever wins; his wealth is therefore not being consumed without his good pleasure.
Nor does this position require us to forbid the race when both contestants contribute the stake, nor to claim that such a case is more deserving of prohibition. In that situation neither man alone is offering his wealth to be taken by the one who beats him; rather, each is simultaneously a giver and a potential recipient. They are equal in their outlay and their effort, and Allah grants victory in the race to whom He wills among His creation. Each competes for his own sake, hoping to retain his own money and win that of his opponent, so neither enjoys any advantage over the other. (2)
By contrast, when only one of them provides the stake, then if he wins his money merely returns to him and he takes nothing from the other, whereas if he loses he must surrender his property. The second contestant, on the other hand, gains the prize if he wins and risks nothing if he loses. Yet contracts are meant to rest upon justice for both sides. This makes it clear that an agreement in which they both contribute the stake is more lawful than one in which the obligation falls on a single party.
The advocates of this opinion have been answered: the Prophet ﷺ gave an unrestricted permission for staking prizes in those three forms of competition, without limiting it to a prize supplied by someone outside the two contestants; therefore his wording embraces the permissibility of