Time and Genesis 1

Beginning
 בראשׁית ברא אלהים את השׁמים ואת הארץ׃
In the beginning God created the heaven and the earth.
Gen 1:1

The Hebrew word Bereshit, in the beginning implies time.

The word can also be understood as "in the first one God created the heaven and the earth."


Days of Creation
Creation takes places in sequence of days and nights that imply the presence of time. These days of Creation happen on the basis of Light that exists before the creation of the Sun.

And God said, Let there be light: and there was light. And God saw the light, that it was good: and God divided the light from the darkness. And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day. 
Genesis 1:13-15 KJV

Also elsewhere in Genesis the passing of time is usually expressed with the concrete word yom, day, as in "his days" rather than using some word for the abstract concept of "time".

Biblical day begins when Sun sets - according to rabbinical rules this takes place exactly when three stars are visible on the night sky over Jerusalem (or Babylon).

The rhythm is expressed in the Creation story. King James translators may not have quite understood the Hebrew expression means and created a monster sentence
"and the evening and the morning were the fourth day".


Late the beginning of night which is especially important for the marking the Shabbat is defined very accurately using astronomical data.


Signs of times
God sets Sun, Moon and stars on the firmament (raqia) for the soon to be created humans as signs to show the passing of time. This is the first thing and the second purpose is to shine light upon Earth!

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: And let them be for lights in the firmament of the heaven to give light upon the earth: and it was so.
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.
And God set them in the firmament of the heaven to give light upon the earth, 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. And the evening and the morning were the fourth day.
Genesis 1:16-19 KJV

KJV translation is not very clear with the fine concepts of time. For example, the New International Version tries to improve:
And God said, “Let there be lights in the vault of the sky to separate the day from the night, and let them serve as signs to mark sacred times, and days and years, and let them be lights in the vault of the sky to give light on the earth.” And it was so.
Genesis 1:14 NIV


Hour
In the time of Genesis life is rather relaxed and there are no hours and minutes not to speak of seconds. However, elsewhere Bible uses the concept of "moment" and the Babylonian 12 moments system is in use for counting the hours of days and nights.

Week
The concept of seven days week is visible in the structure of the Genesis. The names have no special names as in Greco-Roman culture and later but are named by numbers also in modern Hebrew  "First day" "Second day". Only the seventh day has a special name derived from the word shbt "to rest". Sabbath is the Day of Rest.

Month
Bible uses Lunar calendar to define sacred times. It causes difficulties because the heavenly moon clock is not exactly following human calculations and shifts by time. Adjustments were necessary from the beginning.

Also Sun based calendars have problems as we know and fix our calendars by adding a day to February once every fourth year.

But as Genesis says, Moon rules!

Year
In the Biblical world and in the ancient Near East There are twelve moments in the day and in the night and twelve lunar months in the year.