I have no idea what you’re getting so upset about.
If I took a poll of 1000 people taken at random and asked them “What document is Christianity based on?” I am pretty sure *most* (probably all) would say “The Bible.”
And, if I then asked the same people what document is Islam based on, I am pretty sure *most* (if not all) would say “The Quran.”
That is the entirety of what I meant.
Now, if you want to contest that, and argue that Basil or Chrystostom or Augustine or Aquinas is as much a “source document” as the Bible is, that’s entirely your prerogative. But I would be obligated to point out that the Orthodox think that Aquinas was a nut and are suspicious of Augustine’s juridicial views, the Catholics do not view Chrystostom with anywhere near the reverence of the Orthodox (and have no use for latter day Orthodox saints such as Theophan the Recluse), and the Protestants think that both groups are heretical.
HENCE, it’s kind of difficult, when using the term “Christianity” in its most inclusive sense (e.g., all Trinitarian Christians) to refer to any writings other than the Bible as being a “source document” when large percentages of inclusive Christianity either reject them or hold them in suspicion.
Obviously, each subgroup within Christianity has its own opinions as to what constitutes “source.” The Catholics have their Doctors of the Church, the Orthodox have their Three Hierarchs, the Protestants have Luther and Calvin, and the Neocharismatic Evanglicals have Joel Osteen. I acknowledge all that. When I used the term “source”, I referred to the common denominator with which all (I assumed) would agree.