His book of invocations, known as as-Sahifah al-Kamilah (or, as Sahifah as-Sajjadiyah) is a treasure of spiritual, theological and ethical knowledge. One of his most important but less-known works is his Risalatu’l Haquq (The Charter of Rights), which is hereby presented to our English-knowing brethren, with the hope that they
may use it as a guide in their dealings with the people.