I think we need to clarify.

We cannot SEE oxygen, but we can test for it, measure it, and we know it's there. We can alter it, change it, bottle it up and sell it.

God on the other hand, is nothing more than an imaginary friend. There is no evidence, no proof, nothing to even suggest the actual exsistance of this thing outside of the bible. People? No, people got their information from the bible being passed on through the years.

Lets think, imagine for a min. Imagine there was no bible. Where would people even get this idea for a god from? What would prompt them to come up with this "god"? Why would they? I mean, breathing, you can at least see someone doing it. You can then assume that they are breathing the air, sure you don't know all the details of it but you can at least identify a baseline of where someone would have first noticed it. But god... this is just made up being in peoples heads, a catchall for unexplained things. The devil, is the catchall for the bad things that happen, or at least the things that people don't want to happen. It's just bullshit.