Is the consent of the beneficiary necessary for the validity of the guarantee?
Chapter on Guarantee (Daman)
Al-Mughni
Book of Assignment (Transfer of Debt)
Primary text
The consent of the beneficiary (Madmun lahu) is not required for the validity of the guarantee. The evidence supporting this is the precedent set by Abu Qatada guaranteeing a debt to someone the Prophet did not know, and Ali (may Allah be pleased with him) guaranteeing a debt to someone unknown. Furthermore, since guarantee is a voluntary undertaking of a financial obligation, the knowledge of the recipient of the voluntary gift is not required, just as in the case of a vow (Nadhr).
Supporting text
Abu Hanifa and Muhammad hold that the consent of the beneficiary is required because establishing a financial right for another human being is only valid with their consent or the consent of their representative, paralleling sales transactions.