Mas'udi's al-Wajib fi'l-Furud

"Al-Wajib fil-Furud wal-Lawazim" (The Obligatory in the Duties and Necessities), one of al-Mas'udi's books on jurisprudence, and one of the lost books. ²

It covers what people have said about washing and wiping the feet, wiping over leather socks, the sunna divorce, the waiting period, and transgression. Al-Mas'udi mentions it together with "Al-Istibsar" and "Al-Safwa" in the report on temporary pilgrimage and women. ²