Mathematical Bias and the Biblical Calendar
(Revised 2021)

By: Shawn Richardson

Section 3:


We are all probably aware of our mathematical bias is when it comes to days on a calendar. Here is where we break out our stopwatches, measuring the passing of time in hours, minutes and seconds. For the purposes of a physical calendar, we have been conditioned to visualize each square representing a fixed 24-hour period. We transition from one day to the next starting at midnight, or 12 a.m. (or 12 ante meridiem, meaning "before midday").

Most may realize, if they've ever given it any thought, that the Bible never references days in this matter. This is because Adam, Moses or any of the disciples never had access to a Rolex or a smart watch to wear on their wrists. The modern clock, providing a more precise mathematical and universal time for all, was not invented until the sixteenth century. Prior to this, time was measured directly using the movement of the sun, moon and stars. Eventually, man did invent additional tools to assist them, such as sun dials and hour glasses. Even though man's intellect has increased over time, it does not mean that Yehovah, the God of the universe that grants man wisdom, intended to rely solely on man-made tools. His timepiece is never presented in the mathematical measurements of hours, minutes, and seconds, nor did He establish time zone boundaries (and certainly not daylight savings time). So, what did Adam and Moses constitute as a Biblical Day?

If we remember Genesis 1, during the six days of creation, each day consisted of an evening (night) and a morning (day). Genesis 1:3-5[1] states:

As a side note, some believe that this verse refers to the creation of the Messiah Jesus (Yeshua), who referred to Himself as the "light of the world" in John 8:12. However, this idea is debunked by John who also explains in chapter 1 of his gospel that this light was created by the Messiah Himself:

Yes, Yeshua Himself was the Creator in Genesis 1, a feat He could only accomplish, of course, through the power of the Heavenly Father, Yehovah. He confirms this in Mark 5:10 where Yeshua says:

It's unlikely Yeshua would have created Himself. In either case, It wasn't until the Fourth Day of Genesis 1 that the motions of the sun and moon were ordained (or set) by the Creator - meaning the first three days may never have been anywhere near the 24-hour period of length we observe days to be today.

Joshua 10:12-13 tells an interesting story often referred to as Joshua's Long Day, where Joshua prays to Yehovah for both the sun and moon to halt their movements to assist them in their battle against the Amorites at Gibeon. Yehovah obliged Joshua, doubling the length of the day. This rare event should serve as a witness to us that our God does not measure time in fixed mathematical formulas or with the watches we wear on our wrists. Rather He controls the ordained signs of Genesis 1:14. As observers of those signs, we can be confident marking the passage of His time by viewing them and knowing they are of God - regardless of how long our watches indicate it takes for them to accomplish their expected trajectories within the sky.

Start of the Day

So, exactly when does the Biblical Day begin? Many may presuppose their mathematical bias here believing it still begins at midnight (or at least the middle of the night). If you know of someone or are at all familiar with the weekly Sabbath, a day Yehovah commands for us to do no work (Exodus 20:8-11), you will find most begin that Sabbath day rest at sundown on Fridays until sundown on Saturdays. Although most Biblical scholars agree that the Bible measures full days from sundown-to-sundown, let's first take a look at whether there may be some other possibilities.

There are arguments that the Biblical Day begins when the sun rises. The greatest support for this theory likely comes from the synoptic gospels of Matthew, Mark and Luke that describe the crucifixion of Jesus beginning at the third hour (Mark 15:25), which would take place at approximately 9am on our modern clocks - three hours after sunrise (or as the sun is half way up in the sky). Darkness then covered the land from the sixth hour to the ninth hour (Matthew 27:45; Mark 15:33; Luke 23:44), from around noon to 3pm (or when the sun is ordinarily directly overhead and drops half way down in the sky). His death then happened at the end of that ninth-hour. While it was true that Jews counted hours of the day starting with the rising of the sun in that historical period, this was only done in measuring the day-time portion of the full day. At night, time was generally measured in 3-4 hour segments, cumulatively referred to as night watches (Luke 12:38), which lasted throughout the night-time portion of a given full day. It could also refer to the Romans method of telling time that, historically, also used two 12-hour systems to measure both the daytime and nighttime portions in a similar manner[68]. Since Genesis 1 includes both one daytime and one nighttime portion, the ultimate question here would be: which comes first, the daytime or nighttime?

There are several examples in scripture that describe the day as starting and ending when the sun goes down. For example, Exodus 22:26[1] states:

Leviticus 22 describes several scenarios, starting in verse 4, where one would be considered ceremoniously unclean and unable to partake in offerings if they touched a leper or corpse. To be considered cleaned, it was required to bathe and wait until after the sun goes down. Verse 7-8 states:

This infers that if one were to touch a corpse after the sun had already gone down, they would have to bathe and wait until after the following sundown.

Other examples of the going down of the sun include Deuteronomy 16:6, 24:13, Joshua 10:27, Judges 14:18, II Samuel 2:24, 3:35, I Kings 22:36, II Chronicles 18:34, Ecclesiastes 1:5, Jeremiah 15:9 and Daniel 6:14.

Clearly Yehovah understands the concept that the sun doesn't actually go down, as it is the earth that moves in relation to the sun. There are some that reinforce the use of mathematics over observation of Yehovah's signs, believing you must calculate theoretical, conceptual events that are unseen (or invisible). For example, they may argue that the sun continues to go down after it disappears behind the horizon, even though we cannot see it. In other words, the sun only stops going downward when it is at its lowest point below our feet with the earth between us and the sun and just before it begins its turn back upward again - this particular moment is referred to as Solar Midnight. This method would require us to be given a full understanding of the celestial movements of the sun, moon, stars and the Earth in all their complexity along with mathematical variables and formulas to determine these moments, which simply do not exist in scripture. If this were Yehovah's intention for us to create a purely mathematical calendar, then why would time be referenced so consistently from the simple perspective of an onlooker right here on earth?


There are also references to the end of the day as being "between the evenings," or ben ha arbayim. The word evening is another bias we often apply with the modern meaning of being night-time (or the time between sundown and midnight). It's important to note that there is more than one time of the day referred to as evening (or "even" as the King James phrases it), and it doesn't always mean night-time. Rather the word evening, traditionally and within scripture, can refer to the afternoon and can imply various times of the day depending on its context. When given in the plural sense, such as "between the evenings," the first evening generally takes place about an hour, or more, before sundown (or at some point of the going down of the sun), whereas the second evening occurs as it becomes night, or at sundown. An example of this can be derived from Deuteronomy 23:11[1] that says:

Here, evening is described as the point prior to the sun setting when a person should wash with water between evening and sundown. This is also the time of day when the evening sacrifices were made at the alter of the temple - one of two daily sacrifices to be given in the morning and in the evening (late afternoon) as commanded in Exodus 29:38-42, Leviticus 1:1-17 and Numbers 28:1-5. Yet, other scriptures describe evening taking place immediately at sundown, as described in Joshua 8:29[1]:

The evening here is explained as being at the time of sundown. Joshua was following the Torah's instruction in Deuteronomy 21:22-23[1] regarding the handling of dead bodies of those put to death:

Leviticus 23:32, on the other hand, describes observing the Day of Atonement (the 10th day of the seventh month according to verse 26), starting from the ninth day of the month "at evening, from even until even". This can be confusing to us English readers when we see this. If we look closely, though, we can see this verse uses the singular evening. This means the Day of Atonement should be observed starting on the ninth day at sundown, from sundown to sundown - or the entire tenth day of the month. This verse is clarifying the context of the first evening to mean the evening that begins the day (or sundown) and not one that takes place in the afternoon when the daily sacrifices are made.


There is another portion of time immediately following these two evenings, after the sun goes down and having total darkness, which is also referred to as dusk or twilight. When twilight concludes, it is known as tzeit hakochavim. In Hebrew, it refers to the time when at least three stars become visible in the night sky. If you will remember, Genesis 1:14-19 gave us three signs that are used in the Biblical Calendar - the sun, moon and stars. We are also given three functions that these signs provide. The first rules over the day - the sun would clearly play that role here. Although the moon can be seen during the day at particular phases, it certainly does not overpower the sun's light. The second and third signs fill the two remaining requirements: to rule over the night and to separate the day from the night. Since the moon can be seen at all times of the day depending on where it is in its cycle, it obviously does not separate the day from the night. However, when visible in the night sky, the moon does dominate as being the more powerful light source. Therefore, the moon rules over the night and the stars serve to separate the day from the night. Stars only appear to an observer starting at this time of night, in the short interval of time after the sun goes down. While the specific rule of three stars is not mentioned in scripture, it definitely fits their role (and it does mention stars, plural).

A very specific example of the Biblical Day is given in Nehemiah 13:15- 22 where the Weekly Sabbath is clearly described in verses 17 and 18 as being profaned, conducting business of selling goods that was not allowed on the Sabbath. Verse 19[1] says:

We see here the gates were closed 'as it began to be dark'. This only happens when the sun goes down. The story continues in verses 20-21[1]:

We see here that the Sabbath began with the night-time portion when the merchants would camp out after the gates had closed and after the setting of the sun where they waited overnight.

These examples show the Biblical Day beginning right after sundown. Combined with Genesis 1:14, which gives us the sign of two or more stars signaling the division of day from night, we can then specify the Biblical Day as being from twilight-to-twilight. This fulfills the role of the stars and when the sun's light no longer dominates the sky.

There aren't too many controversies over this method for determining the Biblical Day, with most keeping the Seventh-Day Sabbath beginning right at sundown - likely because any differences in opinion (including sunset - civil, nautical or astronomical) usually only span a matter of a few minutes. While this can be frustrating to those looking for a very specific point to base their mathematical measurements, you will find that scientific precision is not emphasized in the Bible - all the more reason to overcome our bias toward relying on mathematics.

Our Developing Bias

Some will still find arguments against observing the sun or stars using extreme outliers, such as: how can you observe the Sabbath when you're above the Arctic Circle or below the Antartic Circle where days are irregular and the sun doesn't shine for months at a time? This argument used to be more theoretical, but in our modern times many do find themselves in such a predicament where they experience a long polar night. In most of these cases, man-made tools are needed as a reference, such as watches, to determine the time of day. Many will mark the last known time the sun dipped below the horizon prior to the long polar night and use this as a reference point to begin and end each day until the sun can be seen again. But does this mean observing the signs given to us in the Bible are not valid? Of course not! Sometimes, we are forced to use good old common sense.

For example, when storm clouds fill the sky and the sun or stars cannot be seen, we may have to determine the start of the Biblical Day using alternative methods - including mathematics. If we are actively practicing observing His signs, we will become accustomed to the approximate time these events should occur. But the ordained signs of Yehovah should always trump any other method that may be used, even if only temporary.

There are other man-made traditions for starting the Biblical Day given by Orthodox Jews who begin the Sabbath by lighting a Shabbat candle (or lamp) precisely 18 minutes before the sun goes down. Alternatively, they may light the candle when the sun is no longer seen by an observer on the treetops. Certainly these are rules never given in scripture. Rather, they are found in the Talmud (for Shabbat 35b), which also add definitions for the size of stars to be seen to fulfill the moment of twilight - they had to be medium stars, not too large and not too small.

Observing days, directly using the sun, was a very common practice, historically, until very recent. The advent of traveling via train cars in the late 1800's led to the standardizing of time worldwide. Prior to this, local time within each town was generally marked by observing High Noon, or the moment the sun's trajectory stops rising above your head and begins its turn back toward the opposite horizon. This concept is the opposite of Solar Midnight.

Many towns would mark a High Noon event with a ball attached to a pole located in the center of town that would drop from the top of the pole to the bottom, giving everyone a chance to sync their watches to 12 p.m. (or 12 post meridiem, meaning "after midday") at the exact moment the ball completed its fall. This concept is the origin of today's New York Times Square event that takes place every New Year's Eve, marking the arrival of the new year on the Gregorian calendar (albeit, in a much more elaborate fashion). This practice would vary slightly from town to town and it often led to confusion for those traveling via the Railroad system. It quickly became evident of the difficulties involved creating arrival and departure schedules for each town because each one set their local time of day based on their local observations. For this reason, mathematical and geographical time zones were created to bring mathematical consistency in calculating and telling time. Other developments, such as the telegraph, also helped play a role that lead city dwellers to change over to the railroad's method for setting the official clocks around town. Clearly this mathematical solution served its purpose well, regrettably it has now become ingrained into our way of thinking when we ponder time itself.

In contrast, Biblical Days remain relative based on differences in geography and seasonal positioning of the celestial objects. This difference becomes apparent based on the moment the Weekly Sabbath begins for different individuals at varying times around the world - even for those located in the same time zone. Due to the curvature of the earth and its axis being titled in relation to the sun as the earth completes its orbit, one person may observe the Sabbath (sundown) up to an hour earlier (or more, in some cases) than the other. As a result, our clocks and practices are now based on an average mathematical timetable that is disconnected from the reality one would observe directly.

Let's consider for a moment if one desired to observe the weekly seventh-day Sabbath and their employer asks them to always work the core business hours of Monday through Friday from 8am to 5pm. This can be an issue in the winter as the sun often goes down prior to 5pm in most locations. This person may decide, for convenience sake and to please their employer, that they will self-appoint the weekly Sabbath to be observed 6pm-to-6pm, ignoring when the sun actually goes down (since it is so annoyingly inconsistent throughout the year). They may even convince themselves that they're still making an honest attempt to keep Yehovah's Sabbath. After all, they could still keep a full day's sabbatical rest for 24-hours, it just happens to extend into the next Biblical day slightly after sundown. Possibly 6pm could be considered the average time the sun goes down throughout the year and the consistency of being at 6pm would be mathematically predicted by others who may work in other locations outside of the office.

Of course, now you have allowed a man-made concept to define the Biblical Day. This type of negotiation of giving into our mathematical bias sets a bad precedent for recognizing His timepiece. Remember Deuteronomy 12:32 that says[1]:

Most who have kept Yehovah's Sabbath have accepted and grasped the Biblical concept of observing the sun (and possibly the stars) and not relying solely on a standardized timetable or a calculated average like 6pm-to-6pm, to know when it should begin. In fact, the verse above would indicate such a practice as being sinful and contrary to Yehovah - especially when they know better.

Many have been raised and taught, as a child, the simple concept of observation. If one is new to keeping the Sabbath, however, it can take some time to make the adjustment for thinking of days differently than midnight-to-midnight on our clocks. While there are mathematical tools that can assist us in knowing what time the sun goes down in our local area, it's still an approximation and would not account for visibly acknowledging if any stars are in the sky. In either case, if one method differs from the other, it is ultimately the sun & stars that we should observe and comply with according to scripture, not man-made concepts based on calculations, rules or average timetables. When we actively observe Yehovah's signs regularly to begin the Biblical Day, it can be a first step for many in overcoming their mathematical bias and the lessons learned from this practice are foundational as we look further into the remaining components of the Biblical Calendar.


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