The Scriptures tell us that “in the beginning” Elohim created the heavens and the earth. We then read about the creation of time known as a day, which then led to a seven day period known as a week. Up to that point, both of these categories of time involve the sun as the sole determining factor of their duration which, of course, was controlled by the earth’s rotational speed. The setting and the rising of the sun marked the progression of the day cycle, and the week was merely a counting of days. This is expressly provided in the Scriptures.