Why did god create a world we need to be saved from?

If god was all-knowing he would have known how the world will turn out, if he didn't want us to sin, it would be his own stupidity creating us, if he knew we would sin. Why does it seem like this god is not omniscient and omnipotent. Why would he create people that use their freewill in a way that he doesn't approve of and then saves them from it if they believe in something written in a book that any human could have wrote and why does he punish those that isn't gullible enough to believe in a single book?