For a millennium, the waqf (Islamic trust) has financed Islam as a society, although more recently it has been on the decline. This article examines the grounds for the success of the waqf; the primary one being its solid foundational structure, developed by jurists benefiting from the flexibility of Ijtihad that praises the waqf to be compatible and adaptable to any substantial changes. This article also establishes that the decline cannot be attributable to its foundational basis, nor to the legal doctrine but rather to factors unrelated to its legal theory. The decline can strongly be linked to the absence of an entire Islamic legal system that can accommodate the waqf. Another crucial factor is the political impact; in Muslim countries the main reason was the control of its assets in order to strengthen their existence. In Palestine, the grounds are different; with the need to acquire land and constrain Palestinian political aspiration.