Generally we assume that God is omnipotent, and could have created the world in a single day/act, so He must have had a reason to organize creation into 6 days. Why?
In other words:
- Why didn't God create the world in one big act of creation?
- Why did God choose to create the world in 6 days, as opposed to any other number? (Probably related to this question when you count in the Shabbat day.)