A term that is used to explain how Hashem created the world is צמצום, or constriction. The idea here is that Hashem’s greatness and true essence cannot be comprehended by man. This is because Hashem is on a completely different plane than man. Truly great people understand this and they remain humble for in comparison to G-d, they realize how small they are.
The inability to truly perceive G-d, forced Hashem to constrict Himself so that humans could get some kind of a glimpse of this holiness. What we are able to see is צמצום, or a fraction of what Hashem really is.
As we start the Torah over again with בראשית, it is necessary to restate basic principles connected with creation. We must never fall into a situation where we make assumptions where we claim that we can second guess how Hashem runs the world. צמצום helps drive home this point.