This book explains one of the important letters written by Imam al-Mujaddid, may Allah have mercy on him, and he called it Fadl al-Islam because it is the first chapter of this letter, in which he explains the explanation of Islam, in which he explains the virtue of Islam, in which he explains heresies, and in which he explains the parameters of true affiliation.

The book deals with the description of the Prophet's pilgrimage in a simple and smooth manner, and Dr. Othman bin Muhammad Al-Khamis relied on clarity and avoidance of complex terms and excessive length.