First of all, God is not real. And if He was real, do you really think that He would choose to communicate with humanity and lay out His entire divine plan in one book that doesn't even make any fucking sense and then a few hundred years later change His mind about it and put out a second book that contradicts the first one and is equally inconsistent?
And that's just if you're a Christian. Some people think that he repeated the process again after that.
Secondly, while there is a Jesus no one has any idea what he said because they didn't bother to write it down. The whole thing was written twice removed (by some guys that knew some guys that knew Jesus)... and that's according to the people that believe in the fucking thing!