Let us begin by remarking that the name itself of Allah is common to Jahiliyyah and Islam. When, in other words, the Qur'anic Revelations began tu use this word, it was not introducing a new name of God, a name strange and alien to the ears of the contemporary Arabs. The first problem, then, that we must answer is: Was the Qur'anic concept of Allah a continuation of the pre-Islamic one, or did the former represent a complete break with the latter? Were there some essential - not accidental - ties between the two concepts of a common word used for two different objects?
In order to give satisfactory answer to these initial questions, we will do well to remember the fact that, when the Qur'an began to use this nakme, there immediately arose serious debates among the Arabs of Makkah. The Qur'anic usage of the word provoked stormy discussions over the nature of this God between the Muslims and Kafirs as is most eloquently attested by the Qur'an itself.
What does this mean from the semantical point of view? What are the implications of the fact that the name of Allah was not only known to both parties in their discussion but was actually used by both parties in their discussion with each other? The very fact that the name of Allah was common to both the pagen Arabs and Muslims, particularly the fact that it gave rise to much heated discussion about the concept of God, would seem to suggest conclusively that there was some common ground of understanding between the two parties. Otherwise there could have been neither debate nor discussion at all. And when the Prophet addressed his adversaries in the name of Allah, he did so simply and solely because he knew that this name meant something - and something important - to their minds too. If this were not so, his activity would have been quite pointless in this respect.
(From chapter 4 - "Allah")
Author: Toshihiko Izutsu
290 pages, hard bound