We do not say anything except what our Lord has said...
We do not say anything except what our Lord has said; so, whenever I provide you with any answer, it is from the Messenger of Allah; we never express any of our own views.” People of knowledge and scholarship know such facts about the Imams from Ahlul Bayt; they never recorded one single statement made by any of them claiming to follow his own view, or resorting to analogy, or to preference..., or to anything besides the Holy Qur'an and the Sunnah.
Even if we refer to the great religious authority the martyred Ayatullah Muhammad Baqir al-Sadr, may Allah be pleased with him, we will find him indicating in his book of instructions ( risala ) to his followers titled Al-Fatawa al-Wadiha (the clear religious verdicts) the following: We find it essentially important to briefly point out to the major references upon which we relied in order to derive these clear verdicts which, as we indicated when we started this discussion, are: the Glorious Book of Allah and the sacred Sunnah as transmitted by reliable transmitters who fear Allah when transmitting anything regardless of their sect.[^3] As for analogy, or preference, or the like, we see no legislative basis for depending on them.
As for what is called the rational evidence about which mujtahids and scholars of hadith differed, whether or not it should be acted upon, although we believe that it can be acted upon, we never found even one legislative injunction whose proof depends on the rational evidence applied in such sense. Instead, anything rationally proven is also fixed at the same time by the Book of Allah or by the Sunnah.
As for what is called consensus, it is not a [third] source besides the Book of Allah and the Sunnah; rather, it is not relied upon only because it can sometimes be used as a means to prove certain points.
Hence, the only two sources are: the Book of Allah and the Sunnah, and we supplicate to Allah to enable us to uphold them, for “Whoever upholds them upholds the secure niche which is never loosened, and Allah is all-Hearing, all-Knowing.” ^4 Yes, we find this to be the dominant phenomenon prevailing upon the Shi`as in the past and the present, and they do not depend on any source other than the Book of Allah and the Sunnah, and we do not find even one of them issuing a verdict based on analogy or preference.
The incident involving Imam al-Sadiq and Abu Hanifah is well known. It demonstrates how the Imam prohibited Abu Hanifah from applying analogy in deriving verdicts.