I've read it and know the story well. I don't think their disobedience was a surprise to God. But if you know that story then I'm betting you know about the new testament as well. The part where god cut out the need for any man to follow a law and instead just have a relationship with him. Maybe he did that because of the exodus experience. Maybe he knew we'd still be very disobedient even when we did reach out in faith. Bottom line is believers are still disobedient today. They're just covered by grace.