Excerpt from Is the Earth Young or Old?
Why do we accept the 6 days as literal and not symbolic? For 3 basic reasons:
How else could God have inspired Moses to make it any plainer that these are literal, normal days?
Rule of Biblical Interpretation: A word is taken in its everyday meaning unless there is compelling evidence that it must be taken in a different sense. Nothing in Genesis 1 indicates long periods of time.
Other Scriptures also show 6 days or rapid creation: Exodus 31:17, Psalm 33:9 and 148:5. (II Peter 3:8 does not say one day equals 1,000 years, but AS a thousand years. Context is how time doesn't affect God, rather man is affected by passing of time (can begin to doubt God), but passing of time doesn't affect God's promises.)
See also Matthew 19:4/Mark 10:6, Luke 11:45-52 and Romans 1:20 for indications that the time of man's creation and the Creation in general are viewed in the Bible as being closely linked.