I hate to break it to you, but that notion of God certainly had a beginning.
Of course, I was merely arguing against the 'no true Scotsman' fallacy, not the existence of God. It is no surprise to me that you should regard an argument against the idea that words have intrinsic meaning as an attack on the idea of God. I have repeatedly noted how religious people tend to conflate these two, seemingly unrelated topics. This lends greater credence to my belief that religious belief stems from an error in perception, where language has become so primary in our understanding of the world that people subconciously think that language pre-exists and shapes the world. Indeed, this is clear in scriptures. "In the Beginning there was the Word." for example. This is the mistaking of symbol for reality taken to the extreme. That error is common in religion. Not only is the word mistaken for God, the book where the words are written, the statue or other icon even music is called God. In reality, these are symbols, but the symbol is so enmeshed in the belief that it is unremoveable. Indeed, could God be merely a collection of symbols given an imagined reality? Plato suggested for every concept, there exists a perfect, ideal prototype. Again, he believed that reality followed the ideas, not vice versa. The concept of the almighty and indescribable God is the logical extension of that idea.
I have gone beyond arguing whether God exists or not. I now argue against the belief that ideas exist independent from reality, that symbols are the thing itself, that words have absolute meaning. These are the faulty foundations that the edifice of religion rests upon.
In our evolution, human beings lived and died according to the effectiveness of their social group. For this reason, exchange of information and social cohesion were of primary importance, and the more successful they were, the more successful the group, and all the individuals within the group. When the length and brightness of one's tail is the primary determinant of a bird's reproductive success, it is not surprising that evolution would produce birds with extravagantly long and bright tails. By the same measure when words and ideas are the most important thing, it is not surprising that people would put exaggerated emphasis on them, causing them, like the tail of the peacock, to become extravagantly exaggerated in their form and importance. So much so that it eventually may become a hindrance, especially in the context of a change in lifestyle, as, for example we have been experiencing more or less continuously for several centuries.