Can you recall when I explained the Hebrew words "echad" and "yachid"? I agreed with the Jewish idea that calling Allah "unique" is more appropriate than calling Him "one" b/c of the issue of singularity being relative to creation. This is simply a matter of human limitation. How else would you define something which existed in and of itself and isn't like anything our minds can conceive? Saying Allah is "One" is the only option we have.
Christian doctrine is not beyond my understanding. I should remind you that you're talking to a former Christian.
Again, you're being illogical! Believing in the Bible b/c the Bible tells you to believe in it is circular reasoning.