We say a biblical day begins at sunset. The day is from sunset to sunset. The lunar Sabbatarians say a biblical day begins at sunrise. They say the day is from sunrise to sunrise.
Let Us Investigate
What is mentioned first in the first chapter of the Genesis creation record—darkness or light?
And the earth was without form, and void; and darkness was upon the face of the deep. (Genesis 1:2)
Darkness was there even before the light was introduced. Logically speaking, the light that came later cannot be placed ahead of darkness in regard to time. That is exactly what the word of God says about each creation day—darkness first, light next.
God then proceeds to make two distinct periods of time where previously only one—darkness— existed:
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. (Genesis 1:3, 4)
God then names those two periods of time:
And God called the light Day, and the darkness he called Night. (Genesis 1:5)
So, “light” and “day” are synonyms, and “darkness” and “night” are synonyms.
And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day. (Genesis 1:5)
There are only two segments in the twenty-four-hour orbit of the earth—light and darkness. We now have different terminologies for the two segments of time in the above verse of Genesis 1:5—light, day, darkness, night, evening, and morning. Light, day, and morning are synonyms. Darkness, night, and evening are synonyms.
Look at the order of the two periods of time:
And the evening and the morning were the first day. (Genesis 1:5)
There are only two periods of time—darkness/night/evening and light/day/morning. So, “evening and morning” means night and day or darkness and light.
How do we know that “the evening and the morning” of Genesis 1 embraces a twenty-four-hour period and not a twelve-hour period, as the lunar Sabbatarians believe?
This same phrase of “the evening and the morning” is used also in the book of Daniel and is clearly a twenty-four-hour period of time. This is the only other place, apart from Genesis 1, where the phrase “the evening and the morning” is used:
And the vision of the evening and the morning which was told is true: wherefore shut thou up the vision; for it shall be for many days. (Daniel 8:26)
How many days are “the evening and the morning” of Daniel?
And he said unto me, Unto two thousand and three hundred days; then shall the sanctuary be cleansed. (Daniel 8:14)
The Hebrew words translated days in Daniel 8:14 are the same words in the Hebrew of Daniel 8:26, where it is translated as “evening” and “morning.” The Hebrew words are ereb and boqer which are the exact words used in Genesis 1 for “evening” and “morning.”
The two thousand three hundred evenings and mornings are two thousand three hundred full twenty-four-hour periods. The lunar Sabbatarians also agree to this. If “the evening and the morning” is a twelve-hour period only, the two thousand three hundred evenings and mornings would be just 1150 days (half of two thousand three hundred days) and would end in AD 694 instead of in AD 1844.
So, if the lunar Sabbatarians agree to the two thousand three hundred evenings and mornings as two thousand three hundred twenty-four-hour days, then it is inconsistent to interpret “the evening and the morning” of Genesis as just compassing twelve hours.
From the very first chapter of the Bible, we see when a new day begins. It begins in “the evening,” at darkness.