But in what span of time was it created? For the following reasons, scripture is clear that it happened in six literal 24-hour days.
(1) The Hebrew term יוֹם, “day,” when it appears as it does in Genesis 1, as a singular noun that is not part of a compound grammatical construction, refers exclusively to normal, 24-hour days.
(2) The use of numerical adjectives with the term יוֹם likewise signals literal days. Of the more than 150 uses of this construction in the OT, only one exception to this rule occurs (Zech 14:7, but see also Hosea 6:2).
(3) The use of the phrase “evening and morning” point to a normal day.
(4) The parallel to Exodus 20:9–11 argues strongly for a literal week of successive days (so also 31:14–17):
Six days you shall labor and do all your work, but the seventh day is a Sabbath to the LORD your God. On it you shall not do any work, neither you, nor your son or daughter, nor your manservant or maidservant, nor your animals, nor the alien within your gates. In six days the LORD made the heavens and the earth, the sea, and all that is in them, but he rested on the seventh day. Therefore the LORD blessed the Sabbath day and made it holy.Apart from literal, successive days, this parallel makes no sense at all.
(5) Logically, the sequence of creation demands rapid creation. The trees and flowers created on day three would have required pollinating insects in a relatively short time for their own survival.