The creation narrative in Genesis 1 hangs first on the 24-hour day, then on the seven-day week. (Genesis 1 describes the first six days of creation week; the first few verses of chapter 2 recount the seventh day.)

"And God saw the light that it was good, and God divided the light from darkness. God called the light Day, and the darkness He called Night. So the evening and the morning were the first day" (Genesis 1:4-5 Genesis 1:4-5 [4] And God saw the light, that it was good: and God divided the light from the darkness. [5] And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.
American King James Version×). We see from the account that God established the day-and-night cycle from the beginning. Day and night are functions of the rotation of the earth as it orbits the sun. Clearly the wording of Genesis describes the 24-hour period we are all familiar with. Notice further that God appointed the sun to separate light from darkness and to divide day from night (Genesis 1:14 Genesis 1:14And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years:
American King James Version×).

How long were the days of creation?

Ever since the realization by scientists that the earth's age may be measured in billions of years, well-meaning people have tried to reconcile the biblical account with such scientific findings. Some have theorized that the seven 24-hour creation days were really much longer—possibly epochs lasting thousands or millions of years. To support this idea, some have argued that the Hebrew word for "day," yom, means an unspecified measure of time in Genesis 1.

It is true that yom can mean an indefinite period, such as in the English sentence "That's how things were done in that day." But the context of each of the six days of Genesis 1 makes it clear how long each day of creation actually was. The expression "So the evening and the morning were the first day" in Genesis 1 is repeated for every one of the other five days.

Here we see "evening" equated with nighttime and "morning" equated with daylight, and the two together make up one day. The wording "the evening and the morning" shows this is clearly talking about 24-hour days.

One rotation of the earth on its axis is the unmistakable meaning of day in the creation account. Throughout the history of the Hebrew people, the evening has always signified the beginning of a new day, a specific 24 hours.

However, since that particular expression does not close the account of the seventh day (Genesis 2:1-3 Genesis 2:1-3 [1] Thus the heavens and the earth were finished, and all the host of them. [2] And on the seventh day God ended his work which he had made; and he rested on the seventh day from all his work which he had made. [3] And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.
American King James Version×), some have tried to lengthen the creation Sabbath as well. They reason that the seventh day of creation has not yet ended, even after thousands of years. Thus the earlier six days of creation are thought to have lasted for thousands or even millions of years as well. But does Scripture support this view?

We should note from Genesis 1 that fruit-bearing plants were created on the third day but that the insects to pollinate such plants were not created until a few days later. If this means a few thousand or million years later, how did the plants survive without their symbiotic partners?

We need to realize that the Bible interprets the Bible. Notice Genesis 1:14-19 Genesis 1:14-19 [14] And God said, Let there be lights in the firmament of the heaven to divide the day from the night; and let them be for signs, and for seasons, and for days, and years: [15] And let them be for lights in the firmament of the heaven to give light on the earth: and it was so. [16] And God made two great lights; the greater light to rule the day, and the lesser light to rule the night: he made the stars also. [17] And God set them in the firmament of the heaven to give light on the earth, [18] And to rule over the day and over the night, and to divide the light from the darkness: and God saw that it was good. [19] And the evening and the morning were the fourth day.
American King James Version×: "Then God said, 'Let there be lights in the firmament of the heavens to divide the day [yom] from the night; and let them be for signs and seasons, and for days [yom] and years . . .' Then God made two great lights: the greater light to rule the day [yom], and the lesser light to rule the night . . . and to divide the light from the darkness. And God saw that it was good. So the evening and the morning were the fourth day [yom]." It makes no sense for the meaning of day to change from a 24-hour day or the daylight portion of a day to an indeterminate period lasting millions or billions of years within a few sentences.

The account of the giving of the Ten Commandments confirms how long each of the creation days was, including the seventh-day Sabbath. Exodus 20:8-11 Exodus 20:8-11 [8] Remember the sabbath day, to keep it holy. [9] Six days shall you labor, and do all your work: [10] But the seventh day is the sabbath of the LORD your God: in it you shall not do any work, you, nor your son, nor your daughter, your manservant, nor your maidservant, nor your cattle, nor your stranger that is within your gates: [11] For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: why the LORD blessed the sabbath day, and hallowed it.
American King James Version×summarizes their significance:

"Remember the Sabbath day, to keep it holy. Six days you shall labor and do all your work, but the seventh day is the Sabbath of the Lord your God. In it you shall do no work . . . For in six days the Lord made the heavens and the earth . . . and rested the seventh day. Therefore the Lord blessed the Sabbath day and hallowed it [declared it holy]."

In defining when we are to observe one of God's annual Sabbaths, the Day of Atonement, God tells us that, "from evening to evening [24 hours], you shall celebrate your sabbath" (Leviticus 23:32 Leviticus 23:32It shall be to you a sabbath of rest, and you shall afflict your souls: in the ninth day of the month at even, from even to even, shall you celebrate your sabbath.
American King James Version×). The same principle applies to the weekly Sabbath and all of the annual feast days. (You might want to read ourbooklet Sunset to Sunset: God's Sabbath Rest, to better understand this biblical command.)

Understanding Genesis 1:1-2 Genesis 1:1-2 [1] In the beginning God created the heaven and the earth. [2] And the earth was without form, and void; and darkness was on the face of the deep. And the Spirit of God moved on the face of the waters.
American King James Version×

The first two verses of the Bible are critical in this discussion. "The Genesis prologue presents those historical truths which are the necessary presuppositions for the valid pursuit of human knowledge" (The New Bible Commentary: Revised, p. 81). So let's take a fresh look at Genesis 1:1-2 Genesis 1:1-2 [1] In the beginning God created the heaven and the earth. [2] And the earth was without form, and void; and darkness was on the face of the deep. And the Spirit of God moved on the face of the waters.
American King James Version×.

Both the New International Version and the older Scofield Reference Bible suggest that the expression "the earth was without form and void" (Genesis 1:2 Genesis 1:2And the earth was without form, and void; and darkness was on the face of the deep. And the Spirit of God moved on the face of the waters.
American King James Version×) can be rendered "the earth became without form and void." In other words, something spoiled the original creation described in Genesis 1:1 Genesis 1:1In the beginning God created the heaven and the earth.
American King James Version×and made it necessary for God to restore order out of chaos—which He did during six 24-hour periods followed by a Sabbath rest.

The Companion Bible points out that, in the King James Version (and most subsequent translations), "the verb 'to be' is not distinguished from the verb 'to become,' so that the lessons conveyed" in these first few verses "are lost." It goes on to explain that "without form" (Hebrew tohu) "is used of a subsequent event which, we know not how long after the Creation, befell the primitive creation of Gen 1.1."

(For a detailed account of the rationale and reference sources that point to the possibility of the rendering "became" instead of "was," see "Earth's Age: Does the Bible Indicate a Time Interval Between the First and Second Verses of Genesis?").

Suffice it to say here that God does not create by first making a mess (1 Corinthians 14:33 1 Corinthians 14:33For God is not the author of confusion, but of peace, as in all churches of the saints.
American King James Version×). God told the cherub (angel) Lucifer, "You were perfect in your ways from the day you were created, till iniquity [lawlessness] was found in you" (Ezekiel 28:15 Ezekiel 28:15You were perfect in your ways from the day that you were created, till iniquity was found in you.
American King James Version×). God is the God of perfection, order and beauty. It is either the angelic realm or man's world that makes the messes.

Comparing these different passages, we can infer that an original creation (Genesis 1:1 Genesis 1:1In the beginning God created the heaven and the earth.
American King James Version×) preceded the making of a gigantic waste by Satan (the former Lucifer) and a third of the angels (Revelation 12:4 Revelation 12:4And his tail drew the third part of the stars of heaven, and did cast them to the earth: and the dragon stood before the woman which was ready to be delivered, for to devour her child as soon as it was born.
American King James Version×), who had become demons. Sometime later God accomplished a full restoration during six 24-hour days, followed by the day of rest that created the seventh-day Sabbath (Exodus 20:11 Exodus 20:11For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: why the LORD blessed the sabbath day, and hallowed it.
American King James Version×).

The time gap between Genesis 1:1 Genesis 1:1In the beginning God created the heaven and the earth.
American King James Version×and 1:2 is an unspecified period that could encompass an untold span of years, accounting for the "deep time" that geologists and other scientists have discovered in the last two centuries. So the Bible itself solves the enigma. We do not need to artificially lengthen the seven 24-hour creation days to resolve the problem.

The Reese Chronological Bible, for instance, begins Genesis with the account of John 1:1 John 1:1In the beginning was the Word, and the Word was with God, and the Word was God.
American King James Version×, then goes to Psalms 90:2 Psalms 90:2Before the mountains were brought forth, or ever you had formed the earth and the world, even from everlasting to everlasting, you are God.
American King James Version×, then goes to Genesis 1:1 Genesis 1:1In the beginning God created the heaven and the earth.
American King James Version×, and next, to the verses in the Bible describing the angelic rebellion. Only afterwards does it continue to Genesis 1:2 Genesis 1:2And the earth was without form, and void; and darkness was on the face of the deep. And the Spirit of God moved on the face of the waters.
American King James Version×, which mentions the devastation left from that uprising.

Then, starting in Genesis 1:3 Genesis 1:3And God said, Let there be light: and there was light.
American King James Version×, we have the commencement of the week-long renewal of the earth. Culminating with the creation of Adam and Eve, the week described here occurred about 6,000 years ago.