Is it permissible to borrow a slave to use as collateral (Rahn)?
General Chapter
Al-Mughni
Book of Loan for Use
Primary text
It is permissible to borrow a slave for the purpose of using him as collateral (Rahn) against a specified amount, of a specified kind, for a specified time, provided the borrower uses the slave as collateral exactly as authorized. Ibn al-Mundhir stated there is consensus that this practice is valid because the borrower borrowed it to fulfill a need, which validates the transaction like other borrowed items (A'ariyah). This view is supported by Abu Thawr and the Companions of Ra'y (Ahl al-Ra'y). Evidence supporting the permissibility holds that since borrowing grants a type of usufruct, the precise measure of the debt or its nature is not required, analogous to borrowing land for cultivation. Furthermore, the lender (Mu'ir) does not become a guarantor for the debt.
Supporting text
Al-Shafi'i requires that the amount and nature of the debt be specified because the resulting harm varies based on these factors. Another view attributed to Al-Shafi'i holds that the lender becomes responsible for the value of the slave because borrowing implies the right to a benefit, and since the benefit belongs to the owner, it implies a guarantee.