"This brings me to one final point that is often overlooked

and is the source of significant consternation and confusion. Islam, as the phenomenon that is actually practiced, esteemed, and identified by Muslims as their religious ideal, is the understanding, prioritization, and even appropriation of the Qur'an and Sunna sustained over a long enough period of time to acquire an indeterminate but requisite degree of normative status among a critical mass of religiously literate Muslims. A verse - for example, "And We created human beings" (wa la qad khalaqna l-insan") may be pointed to as proof that there are multiple gods or even that the Qur'an endorses the Trinity. Such renderings, however, not matter how "grounded" in Qur'anic passages they may appear to be, only become a part of "Islam" when those whom critical masses of Muslims recognize as authorities understand, defend, and endorse them as such, and this long enough to confer upon them the status of normative understandings. This, in fact, is the very meaning, function, and significance of Tradition.

-Sherman A. Jackson, Islam and the Problem of Black Suffering, p. 11