he began trading with them, because the recipient claims that he bears no liability for funds with which he has already traded. Reasoning by analogy from Ashhab’s principle, however, would require accepting the recipient’s word even if he had already traded with the funds, since he traded only with funds that their provider had authorized him to use for trade.
As for when the funds have yielded a profit, one view is that it is held in abeyance: whichever party retracts his own account and accepts the other’s account may take it. If the second party then adopts the first party’s original account, after the first has already adopted the second’s account, this retraction does not oblige the party who retracted first to swear an oath.
Another view is that it belongs to the provider of the funds, who may take it. This follows from Ibn al-Qāsim’s position in the Book of Pledges and Ashhab’s position in the Book of Lowering the Curtains, even if the provider persists in his denial. A further view is that he may not take it, even if he adopts the account of the party who acknowledged his entitlement to it. Success comes from Allah alone; He has no partner.