Is the guarantee provided by a slave without his master's permission valid?
Chapter on Guarantee (Daman)
Al-Mughni
Book of Assignment (Transfer of Debt)
Primary text
The guarantee of a slave, whether authorized for trade or not, is invalid without the explicit permission of the master. This view is held by Ibn Abi Layla, Al-Thawri, and Abu Hanifa. The reasoning is that this contract involves imposing a financial liability, which requires permission, just like marriage (Nikah).
Supporting text
A dissenting view suggests the guarantee is valid and enforceable upon manumission, based on the premise that the slave is capable of transacting and the transaction does not harm the master, similar to confessing liability for property damage. If the master permits the guarantee, it is valid because the master's permission validates the transaction.