Current commercial deals are based on a fundamental pillar-credit-which offers the convenience of deferred payments. There are many ways to secure credit including letters of guarantee, bail, cash deposit, credit document, property mortgage, and others. A mortgage agreement is one way to reinforce trust on the debtor's willingness to pay. Thus, Shariah law has provided a set of rules to strengthen the role of mortgage agreements.

The most important rule is the one that concerns possession of the mortgaged property, which comes in two types: first, the creditor owns the mortgage; second, the mortgage is held by a third party who is called in Islamic jurisprudence as an Adel, a trustee of both the debtor and creditor.