Is it permissible to offer a stipulated reward for taking out a loan on one's behalf?
Chapter on Loan (Qard)
Al-Mughni
Book of Sales
Primary text
It is permissible to say, 'Borrow one hundred for me from so-and-so, and you shall have ten.' This is considered a permissible fee (Ja'alah) for performing a permissible act, similar to offering payment for building a wall.
Supporting text
It is not permissible to offer a reward for guaranteeing a debt, such as saying, 'Be my guarantor and you shall have one thousand.' This is invalid because when a guarantor pays the debt, they are entitled to reimbursement from the principal debtor, making the arrangement akin to a loan that garners benefit (Riba), which is impermissible.