He it is who has bestowed upon thee from on high this divine writ, containing messages that are clear in and by themselves - and these are the essence of the divine writ- as well as others that are allegorical.5
Now those whose hearts are given to swerving from the truth go after that part of the divine writ6
which has been expressed in allegory, seeking out [what is bound to create] confusion,7
and seeking [to arrive at] its final meaning [in an arbitrary manner]; but none save God knows its final meaning.8
Hence, those who are deeply rooted in knowledge say: "We believe in it; the whole [of the divine writ] is from our Sustainer - albeit none takes this to heart save those who are endowed with insight.
The above passage may be regarded as a key to the understanding of the Qur'an. Tabari identifies the ayat muhkamat ("messages that are clear in and by themselves") with what the philologists and jurists describe as nass - namely, ordinances or statements which are self-evident (zahir) by virtue of their wording (cf. Lisan al-'Arab, art. nass). Consequently, Tabari regards as ayat muhkamat only those statements or ordinances of the Qur'an which do not admit of more than one interpretation (which does not, of course, preclude differences of opinion regarding the implications of a particular ayah muhkamah). In my opinion, however, it would be too dogmatic to regard any passage of the Qur'an which does not conform to the above definition as mutashabih ("allegorical"): for there are many statements in the Qur'an which are liable to more than one interpretation but are, nevertheless, not allegorical - just as there are many expressions and passages which, despite their allegorical formulation, reveal to the searching intellect only one possible meaning. For this reason, the ayat mutashabihat may be defined as those passages of the Qur'an which are expressed in a figurative manner, with a meaning that is metaphorically implied but not directly, in so many words, stated. The ayat muhkamat are described as the "essence of the divine writ" (umm al-kitab) because they comprise the fundamental principles underlying its message and, in particular, its ethical and social teachings: and it is only on the basis of these clearly enunciated principles that the allegorical passages can be correctly interpreted. (For a more detailed discussion of symbolism and allegory in the Qur'an, see Appendix I.)
Lit., "that of it".
The "confusion" referred to here is a consequence of interpreting allegorical passages in an "arbitrary manner" (Zamakhshari).
According to most of the early commentators, this refers to the interpretation of allegorical passages which deal with metaphysical subjects - for instance, God's attributes, the ultimate meaning of time and eternity, the resurrection of the dead, the Day of Judgment, paradise and hell, the nature of the beings or forces described as angels, and so forth - all of which fall within the category of al-ghayb, i.e., that sector of reality which is beyond the reach of human perception and imagination and cannot, therefore, be conveyed to man in other than allegorical terms. This view of the classical commentators, however, does not seem to take into account the many Qur'anic passages which do not deal with metaphysical subjects and yet are, undoubtedly, allegorical in intent and expression. To my mind, one cannot arrive at a correct understanding of the above passage without paying due attention to the nature and function of allegory as such. A true allegory - in contrast with a mere pictorial paraphrase of something that could equally well be stated in direct terms - is always meant to express in a figurative manner something which, because of its complexity, cannot be adequately expressed in direct terms or propositions and, because of this very complexity, can be grasped only intuitively, as a general mental image, and not as a series of detailed "statements": and this seems to be the meaning of the phrase, "none save God knows its final meaning".