Islamic jurisprudence specifies which foods are halāl (حَلَال "lawful") and which are harām (حَرَامْ "unlawful"). This is derived from commandments found in the Qur'an, the holy book of Islam, as well as the Hadith and Sunnah, libraries cataloging things the Islamic prophet Muhammad is reported to have said and done. Extensions of these rulings are issued, as fatwas, by mujtahids, with varying degrees of strictness, but they are not always widely held to be authoritative.