Is the surety valid for a liability that has not yet become obligatory?
Chapter on Guarantee (Daman)
Al-Mughni
Book of Assignment (Transfer of Debt)
Primary text
The surety for a liability that has not yet become due is valid. The meaning of "Whatever I give to you" refers to what will be given in the future, evidenced by its being contrasted with guaranteeing a right after it has already become due. The difference of opinion and the supporting evidence are the same as in the previous issue. The counter-argument suggests that since surety involves joining one's liability to another's in undertaking a debt, if the principal debtor has nothing upon them, there is no joining of liabilities, hence no surety. However, the rejoinder is that the surety joins their liability to the principal debtor's in that whatever is incumbent upon the principal becomes incumbent upon the surety, which is sufficient.
Supporting text
The opponents concede the validity of guaranteeing something thrown into the sea before it is due, and the companions of Al-Shafi'i allow, in one narration, the guarantee of the reward (ja'ala) in a contractual hiring before the work is done and any sum becomes due.