Adapted from Creation Answer Book by Hank Hanegraaff
Just as there are extrabiblical liabilities for the twenty-four-hour view (speed of light, star life, etc.), so too there are exegetical liabilities*.
First, young-earth creationists* suggest that God employed nonsolar light to govern the days until he created the sun, moon, and stars on Day 4. Yet the biblical text literally says, “There was evening, and there was morning,” indicating that the first three days of creation were normal solar days encompassing daylight and darkness (Genesis 1:5, 8, 13).
Furthermore, the dominant argument that the Hebrew word yom (meaning day) used with a numeral always, always, always refers to a literal twenty-four-hour solar day does not correspond to reality. Hosea 6:2 is a devastating counterexample. Here, as in other passages (Zechariah 14:7), yom preceded by a numeral represents a period of time far longer than a single solar day.
Finally, the unending nature of the seventh day constitutes a major exegetical problem for the twenty-four-hour interpretation. Logically and literarily, the seventh day cannot simultaneously be unending and temporal.
In sum, the days of Genesis are rendered literal solar days not to establish a chronology of creation, but to remember the purposes of God in creation.
For further study, see The Genesis Debate: Three Views on the Days of Creation, ed. David G. Hagopian (Mission Viejo, CA: Crux Press, 2001).