Is it permissible for the Imam and Preacher to issue fatwas without a reference?

The mufti (issuer of religious edicts) is not required to mention the reference if what is meant is the name of the book upon which he relied, because the station of fatwa (issuing religious edicts) does not necessitate that. However, if what is meant is the religious evidence from the Qur'an, Sunnah, and sayings of the predecessors, then he is obligated to be knowledgeable of that. Indeed, it is forbidden to issue a fatwa based on an opinion that contradicts the texts or one for which the texts do not attest acceptance. As Ibn al-Qayyim mentioned concerning Imam Ahmad, it is not permissible to issue a fatwa except for one who is knowledgeable of the Qur'an and Sunnah.