I have found the main reason many Christians try to reinterpret the word day in Genesis and use this passage from 2 Peter 3:8 to justify this is that they really are trying to fit the false millions of years belief into Scripture.
But how will making each day 1,000 years help accommodate millions of years—it won’t!
The Hebrew word for day, yom, is used hundreds of times in the Old Testament, but I don’t hear anyone questioning what those days mean by claiming a day is like a thousand years.
Q: So why is it that they only single out the use of the word day in Genesis 1?
A: Again, it’s because they’re impacted by millions of years, and they’re trying to fit long ages into Genesis 1.
Q: Do we ever hear anyone claiming Jonah was in the great fish for 3,000 years because a day is like a thousand years?
A: Of course not.
Now, if we take Genesis 1 as written, and look at the context for the word day, yom, for each of the days of creation, we can come to no other conclusion than those days are ordinary approximately 24-hour days.
When yom is qualified by night, evening, morning, or number, it always means an ordinary day.
All six days have yom qualified by evening, morning, and number. Day one also qualifies yom with night, and day seven is qualified with a number.
All seven days in Genesis 1 are ordinary days. Yes, the days in Genesis were ordinary days! We need to take Genesis 1 naturally—as written and not try to reinterpret the days because of outside influences."
Ken Ham