His book “Al-Īmān” is considered among the first which was written of the books regarding īmān and the refutation of the Murjiah. In it the author gathered ahādīth from the Prophet (sallAllāhu ‘alayhi wa sallam) and the narrations which were narrated from the Salaf of the Ummah and the leaders of the Sunnah in the issues of īmān.