One of the major problems that we all have (in fact, it’s the same problem Adam and Eve had in the Garden of Eden) is that we tend to start from outside God's Word and then go to what God has written in the Bible (or—in Adam's case—what God forbade him to do) to try to interpret it on the basis of our own pre-set ideas. This is the major reason why most people question the length of the days of creation in the book of Genesis.
If the Bible is the inspired Word of the infinite Creator God, then it must be self-authenticating and self-attesting—and it is. At the same time, my presupposition is that we should start with what God's Word says regardless of outside ideas, for only God's Word is infallible.
If people doubt the length of the days of creation when the language of the Bible speaks so plainly that they are regular days, then they are accepting a particular approach to all of Scripture. Why shouldn't they then start to doubt that Christ's Virgin Birth really means a virgin birth? Why shouldn't people start to doubt that the Resurrection really means resurrection?
The major reason why people doubt that the days of creation are 24-hour literal days usually has nothing to do with what the Bible says, but comes from outside influences. For example, many believe that because scientists have supposedly proved the earth to be billions of years old, then the days of creation cannot be ordinary days.
When people use Scripture to justify that the days of creation are long periods of time, they usually quote passages such as 2 Peter 3:8 , “ ... one day is with the Lord as a thousand years ...” . Therefore, they think the creation days could be a thousand years, or perhaps even millions of years. However, if you look at the rest of the verse, it says, “ and a thousand years as one day.” This cancels out their argument!
The context of this passage concerns the Second Coming of Christ. This particular verse is telling readers that with God, waiting a day is like waiting a thousand years, and waiting a thousand years is like waiting a day because God is outside of time—He is not limited by natural processes and time.
So this passage has absolutely nothing to do with defining the days of creation. Furthermore, there is no reference in this 2 Peter passage to the days of creation.
The Hebrew word for day in Genesis chapter 1 is the word yom. It is important to understand that almost any word can have two or more meanings, depending on context. We need to understand the context of the usage of this word in Genesis chapter 1.
Respected Hebrew dictionaries, like Brown, Driver, Briggs, and also Koehler and Baumgartner, give a number of meanings for the word yom depending upon context. One of the passages that both lexicons give for yom meaning an ordinary day happens to be Genesis chapter 1. The reason is obvious. Every time the word yom is used with a number, or with the phrase “evening and morning,” anywhere in the Old Testament, it always means an ordinary day. In Genesis chapter 1, for each of the six days of creation, the Hebrew word yom is used with a number and the phrase, “evening and morning.” There is no doubt that the writer is being emphatic that these are ordinary days.