What is the illicit money in the usury of delaying the banks' exchange settlement, and how is it determined and disposed of?

Usury is of two types: riba al-fadl (usury of surplus) and riba al-nasī'ah (usury of delay). The forms of usury are three:

1. Riba of debts: This combines riba al-fadl and riba al-nasī'ah, such as a debtor increasing the debt in exchange for delaying repayment. This form is inherently prohibited and is what the people of Jahiliyyah (pre-Islamic ignorance) used to practice. 2. Riba of sales (where only riba al-fadl is present): Such as selling one saa' of good dates for two saa's of bad dates with immediate possession at the time of the contract. In this, there is an increase in quantity without delay. 3. Riba of sales (where only riba al-nasī'ah is present): Such as selling twenty saa's of dates spot for the same amount deferred, or one hundred dollars spot for one hundred euros deferred. This is prohibited because Islamic law stipulates immediate possession before parting. The wisdom behind this is to block the means to riba of debts.

Usury, in both its types, is prohibited. For someone who has entered into a void usurious contract (such as currency exchange without immediate possession), their repentance involves annulling the contract and each party returning what they took. If annulment is not possible (e.g., due to not knowing the other party), then they must repent to Allah the Almighty.