...And since Christianity can and did exist without a codified central text, since it is based around the Word made flesh (not text), it is really not the problem that you may think it is if you can point to earlier stories that you claim are the precursors to Christ. There have always been precursors to Christ and the true religion of God (Christianity), and this fact was happily acknowledged long before the advent of Islam...what else do you think the Old Testament is all about to Christians?
All prophets of God would be, word made flesh, wouldn't they? As they all carry a message in their actions to be lived out in a mong people.
This is a very good point, and following Orthonorm's point about how it is in some sense inadequate to translate "Logos" as "word" due to the associations that that term has (and in fact there is a separate Greek word for the more technical, grammatical/linguistic sense that he points to -- lexis
-- which in some sense frees us to think of "logos" philosophically), we should consider not only as "Word" in the sense of "message" (at which level you are absolutely right that other prophets are also a kind of "logos"), but also in terms traced to the Hellenic Jews who preceded the Christians in places like Alexandria, as these were likely the antecedents to the development of a specifically Christian theology regarding this term. Philo (20 BC-50 AD), for instance, identified the Logos with God's creative power (perhaps similar to what the Eastern Orthodox would call His energies
, i.e., the way He works within creation). Others identify the logos with divine reason, following more closely the Stoics. All of these are acceptable and they are all in some sense correct -- God is, after all, never without His creative power (recall how in the Qur'an, God says "be!" and it is), nor His reason.
So you're not wrong here, either, it's just that there's more to it than that. It's an idea that encompasses all that came before it, and indeed probably goes further than even Philo did, in identifying all of these senses of Logos with one incarnate person (having lived before the incarnation and died only shortly after St. Mark brought the message of Christianity to Alexandria, Philo obviously would not have thought to apply it in that sense, although he certainly had no problem adopting the term to talk about God, and Christians have done nothing else). Following the above, in Christian usage it appears common to relate the logos to the permanence and/or preexistence of God, and hence the permanence and/or preexistence of Christ, as in the fraction prayer for the apostles fast and feast
, which begins by addressing Christ: "You are the Logos of the Father, the God before all ages"
There is a danger in thinking of these concepts in one sense only, which really restricts our view. As early as the first century after Christ, Christian writers such as Justin Martyr (d. 165) were writing about the concept of the "spermatikos logos"
-- "the Word in seed form" -- to argue that there is a 'seed' of the true revelation of God in all non-Christian religions. For Christians, that revelation is obviously complete and perfect in Jesus Christ, but we follow Justin Martyr in affirming this too. I bring this up to show that this is yet another level at which the Word can be affirmed, without claiming anything about the prophets of these various religions being "Word made flesh", as we do not affirm their religions in themselves (think of this as similar to the Muslim stance that not everything in
Christianity is wrong, but Christianity itself is).
So, yes, in some sense you are right that the prophets may be considered similarly, but in the wider view, and more importantly in keeping with historical Christian theology, there is one only eternal "kalimatullah", and that is Christ Jesus.