I have read through the entire thread (all sixteen pages up to now), and I've noticed a great conflict regarding the religious content involved in not only this song but in the game as a whole. I would like to address this in a manner that is as unbiased as consciously.
Undoubtedly, there is a great deal of Christianity involved in the soundtrack of Civilization IV. This is apparent in the entire Medieval Era segment and the introduction screen. It has been pointed out that the Medieval Era was influenced greatly by the spread of Christianity, and this is true. However, it is also true that other religions were very strong. At the time, Islam also greatly influenced its part of the World. Other strong religions and weaker religions flourished in this time period, yet religious music based on those religions are not present. Other posters mentioned that implementing other religious tracks would clash with further more people. The real question I have is, why implement religious tracks at all? Civilization III had a Medieval Era as well, but I don't recall an entire soundtrack segment of Gregorian chants. I recall Baroque and other purely musical scores implemented for that period.
Of course, don't get me wrong--I am not against the music because of each word in the lyrics. But one must consider more than one part to the whole. One must consider the fact that one's personal beliefs have a very strong influence on one's life. One must consider that words are powerful images and can be the difference between love and hatred. One must also relate this case to many external cases, as well. This is not the only time religious clash has occurred. The World is currently full of these clashes regardless of where or on what grounds. On one hand, you have a game that is based off pure history, and history has undoubtedly been influenced mainly by Christianity. On the other hand, you have individual views on the World.
To settle all religious disputes, I believe, is not the task of the producers of this music or of this game. To settle religious disputes, I believe, is to the task of each individual. If you are a person who feels harmed by this music, then find solutions--replace it, remove it ... do something. If you are a person who feels harmed by this game's content, then find solutions--play a different game, find ways to play that do not involve that which brings harm to you ... do something.
Now that I've covered the biggest topic in this thread (which had little to do with the main topic regarding the release of the lyrics of the song), I would like to give thanks to all who contributed in the accurate compilation of the lyrics. Lovely music, interesting song, fun game.