“And God said ‘Let…’”
The phrase “And God said ‘Let …’” is the phrase that begins every new scene in the chronological creation story and “Let there be light” is the first biblical use of the word “let.” There are eight of these phrases each designating a new scene’s start in Genesis Chapter 1, but only six days. Days 3 and 6 both describe two scenes for a total of eight scenes covered in six days. The phrase “And the evening and the morning were…” signifies the end of each day and it occurs 6 times. The seventh day was the day of rest that begins Genesis Chapter 2.
One should note that the biblical chapter and verse designations were added for our modern convenience long after Genesis was written.
In the minds of many, the common word “let” erroneously takes on a separate and irrational meaning in the biblical creation story. Its definition is simply to “allow something to happen.” Let is synonymous with allow. “Let” does not mean something physically exists from nothing. “Let” is not a word that means instantaneous creation. The phrase “Allow there to be light” has an identical meaning. Moreover, one cannot reasonably assume that a change in the availability of light occurred coincident with the command; it merely says that light shall be allowed to exist at Earth’s surface- presumably for the duration of human time. It is unreasonable to expect that the Sun lit-off with this command, but it could have.