So what does the theory assume about the Biblical creation? The obvious answer is that it assumes that the bible is wrong and silly. So what does the big bang theory say about the validity of the bible which states of itself that it is that Word of God? Obvously the theory rejects that though it may try to be polite about it. Either that or it implies that God didn't understand the Big Bang Theory or that God was not capable of explaining it.
The theory does not at all reject the concept of God. It is a simple description of mechanics as well as we can determine them to date.
The theories involving cosmology don’t take a stand on Biblical inerrancy.
They are exactly the same as describing the workings of a short block Chevy based engine that produces 610 HP (available, BTW, as a crate engine).