What's in a name?

Recently, I was involved in a discussion about whether or not it would be appropriate for a Christian to refer to the God of Christianity as "Allah" when speaking to a Muslim. My initial reaction to this question was outright rejection. After all, I believe that the God revealed in Christianity is utterly distinct from the deity of Islam known as "Allah." Therefore, wouldn't a reference to God as "Allah" be a tacit endorsement of the relativistic point of view that sees all religions as basically worshipping the same God? It was then I came to the realization that I was referring to “God” instead of “Theos,” as I would if I were truly concerned with the actual word for “God” found in the New Testament. From there, things only got worse as I realized that the writers of the New Testament were actually using the Greek word “Theos” to refer to “Yahweh” or “Elohim” from the Hebrew Old Testament! As to the pertinent question: what did the Greek word used in the New Testament (and Septuagint) for “God” refer to before it was used with reference to “Yahweh” or “Elohim”? It referred to the “gods” of ancient Greek polytheism!

As such, it becomes clear that it wasn’t actually the word or phoneme that was uttered which was important in designating who it was they were talking about when the New Testament writers used the word “Theos.” More important was the understanding with which they “filled up” its meaning. While there were certainly similarities between the way in which the Greek speakers of the Roman Empire conceived of their “gods,” and the nature of Yahweh, they came to accept the word “Theos” based on the definition of who Yahweh revealed himself to be in the Scriptures.

Perhaps a discussion of the “True Allah” would, in fact, be an appropriate starting point for a discussion of God with a Muslim...Beyond this question, however, perhaps there is an even more important one: How do Christians “fill up” the meaning of “God” in our context, and what response does this evoke? For it was not without reason that Jesus warned, “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only he who does the will of my Father who is in heaven” (Matt 7:21).