Theism is the simple belief in a Supreme Being (most notably a creator of the universe). Christianity is a mere branch of that belief. The three Abrahamic religions proclaimed there to be an almighty, creator God but not all theists follow the Abrahamic religions at all. Some believe God never revealed himself to mankind, which is why you have Deism. Others just believe the God of the Bible or Qur'an isn't the true god. One can believe in a God without believing in an Abrahamic god. Thats all i'm trying to say lol.
Now you mention the Bible....do you mean that if you believe in God, do you have to adhere to the moral teachings of the Bible or are you saying, if you believe in God....do you have to believe the Bible is truth?
Considering I am a strict Kemetic Reconstructionist, and have been one for over a decade, I'm well aware that one can believe in A God without believing in the Abrahamic God. And the fact that I ask if one could believe in God without adhering to the Bible, should have been clue number one that I was asking about the God of the Bible and not the God of the Qua`ran.
I guess I worded my question wrong and placed it in the wrong section, but yes, my question is asking do you (as in the general sense of the word), believe that a "Christian" is, religiously speaking, deserve to be called a "Christian" (or rather, are they considered a.TRUE Christian), if they claim to believe in God yet do not believe ALL of the Bible?
Even I believe in some of the teachings of the Bible, in the moral sense of the teachings (turn the other cheek, do unto others, etc.) As I don't believe Christianity and a moral compass to be mutually inclusive. One can believe in morals and not be Christian. However, my question is asking about the ENTIRETY of the Bible. Not just bits and pieces.