The Glorious Erudite Sheikh Sulayman al-Ahmad, Allah sanctified him, said: "And among the important principles within this noble doctrine is knowing what must be followed by tradition (taqlīd); indeed, the Shu'aybi House—its pillars were built upon the recognition of the Form, meaning the concrete, objective existence (al-wujūd al-‘aynī). These two principles distinguish this noble doctrine from all other doctrines; through them, the monotheist is recognized, and in accordance with the believer's proficiency in them, their academic standing, deep-rootedness in religion, strength of insight, correctness of belief, and adherence to their proper boundary are known.

And our Master as-Sadiq, glorified is his glory, said to al-Mufaddal, unto him be submission: "O Mufaddal, indeed the appearance of the Pre-eternal among His creation is wondrous; none knows that except an expert scholar."

And Muhammad ibn Sinan, unto him be submission, asked our Master as-Sadiq, glorified is his glory, concerning the recognition of the manifestation of the Essence (al-Ma'na) by its very self? Thereupon his eyes welled with tears and he said: "O weak ones, what have you to do with this? Why is it that you ask about that which you possess no capacity to bear?