What is the reality of the ijma' (scholarly consensus) that is established? And is it necessary that the ijma' have a precedent from the Book and the Sunnah?

The questioner : What is the reality of the ijma' (scholarly consensus) that is established? And is it necessary that the ijma' have a precedent from the Book and the Sunnah?

The Shaykh : The ijma' (scholarly consensus) that can be affirmed as valid is only that which is known from the religion by necessity. This is what our Lord (Mighty and Majestic) referred to in the noble verse that we have mentioned on various occasions, namely His saying (Glorified and Exalted is He): . Thus, the path of the believers is the ijma' (scholarly consensus) that it is not permissible to contradict. As for theoretical ijma' (scholarly consensus), it cannot be realized; because scholars differ in their understanding of many texts from the Book or the Sunnah. For this reason, Imam Abdullah ibn Ahmad narrated from his father that he said: "Whoever claims ijma' (scholarly consensus) has lied; how does he know? Perhaps they differed." In this statement, he is referring to the ijma' (scholarly consensus) that scholars call, as I mentioned earlier, theoretical ijma' (scholarly consensus). As for the practical ijma' (scholarly consensus) upon which the Muslims have acted, that is the ijma' (scholarly consensus) that a claimant can validly assert.
The truth is that one who reads the works of scholars of fiqh (Islamic jurisprudence) and scholars of usul al-fiqh (the principles of jurisprudence) finds them differing greatly in their definitions of ijma' (scholarly consensus). Some say—and this agrees with the aforementioned ijma' (scholarly consensus)—that ijma' (scholarly consensus) is the consensus of the Ummah of Muhammad. Some narrow the ijma' (scholarly consensus) of the scholars of the Muslims. Some say it is the ijma' (scholarly consensus) of a specific Islamic country, such as the ijma' (scholarly consensus) of the people of Madinah, which is known to be part of the madhhab (school of jurisprudence) of Malik. Some say it is the ijma' (scholarly consensus) of the people of Kufah, and so on. None of these ijma's (scholarly consensus) can be described as valid. The scholars of usul al-fiqh (the principles of jurisprudence) have these various differing ideas. The statement of Imam Ahmad applies to all claimed ijma's (scholarly consensus) except the first one; which is the ijma' (scholarly consensus) of the Ummah, and that is the path of the believers.