On the fourth day of creation God created the Sun, the Moon and the Stars. Arguably, this is the start of the 24-hour clock on Earth. in Genesis 1:14-19 we are told the following:
14 Then God said, “Let there be lights in the firmament of the heavens to divide the day from the night; and let them be for signs and seasons, and for days and years; 15 and let them be for lights in the firmament of the heavens to give light on the earth”; and it was so. 16 Then God made two great [d]lights: the greater light to rule the day, and the lesser light to rule the night. He made the stars also. 17 God set them in the firmament of the heavens 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 So the evening and the morning were the fourth day. (NKJV).
So, why do I make issue out of the 24-hour clock not starting until Day Four of Creation? I do so because God devoted an entire day to creating the Sun, Moon and Stars that light the Earth. That is the sole purpose of this day. Those who contend that all six days of creation were on a 24-hour clock support their contention by examining the meaning of the one word translated “Day.” Why would those who do this ignore the express statement in Genesis 1:14-19 that the 24-hour clock was not in place until God created the Sun, Moon and Stars to light the Earth?
This passage further indicates the beginning of a 24-hour clock on day four of creation by noting the Sun, Moon and Stars will serve as signs and seasons. The Sun, the Moon and the Stars and their actions are constant. We can tell the season by the temperature on earth and the alignment of the moon and the stars.
The light provided by the Sun is separated into night and day by the rotation of the Earth on its axis. The Moon provides a reflection of the Sun’s light during most nights. The seasons are controlled by the rotation of the Earth around the Sun. This is how we arrive at our 24-hour clock and the calendar year. Thus, the 24-hour clock did not start until day four of creation.
The creation of the Sun, the Moon and the Stars sets the stage for days five and six of creation. On these days, God creates animal life and human life.