Hence, if we suppose that a person is obliged to pay, for example, five hundred sāʿs (a traditional measure of volume), and he has a vessel that holds ten sāʿs and wishes to calculate the rest by repeatedly filling that vessel, there is no objection. When the substance is uniform, such estimation is permissible—following the practice of Abū Bakr al-Ṣiddīq (may Allah be pleased with him). Allah alone grants success.