LCN Article
The Hebrew Calendar - Part 1: Is It Valid for the Church Today?

November / December 2000

John H. Ogwyn (1949-2005)

Since 1986, the calendar has been a recurring source of doctrinal controversy in the Church of God. Many articles and papers have proposed different methods of calculating the dates of the annual festivals, and at least a half-dozen different calendars and calculation methods have been offered.

This has troubled many sincere brethren who want to do what pleases God. With all the controversy, they are unsure. But does God really expect each individual Church member to become an expert on calendar matters?

We can understand the “calendar issue” by asking three simple questions, and then answering them from the Bible. Do the rules of the current Hebrew calendar conform to Biblical principles and guidelines? Does God expect each Christian to determine the calendar for himself, or did He entrust some authority to make calendar decisions? And can we really know what calendar Jesus Christ and His Apostles used?

Is the Hebrew Calendar Based Upon the Bible?

Does the Bible give guidelines regarding the calendar we should use in observing God’s festivals? If so, what are those guidelines and where do we find them? First, let us ask whether the calendar should be based on physical sighting of the new moon, or whether it should be based on calculation. Some argue that the only valid way to begin a new month is to actually see the faint crescent of the new moon. Does the Bible resolve this argument? Absolutely!

The Hebrew word chodesh is translated “month” in most English language Bibles. Its root meaning involves “making new” or “repairing.” The moon orbits the earth, going through its phases as its position changes in relation to the sun and the earth. Approximately every 29-and-a-half days, the moon comes into exact conjunction between the earth and the sun, and the three orbs are in a straight line with one another (though not necessarily on the same plane). In conjunction, the moon is totally dark, reflecting none of the sun’s light. As it moves westward, away from conjunction, it again begins to reflect light. Depending on the observer’s location and the earth’s position at conjunction, the new moon will generally not be visible until one or two days after the conjunction.

Note that basing the new month upon physical sighting of the new moon would require keeping the Feast of Trumpets for two days! An observer cannot know, in advance, on which day he might see the new moon. Depending upon the exact time of conjunction, he might see the crescent on either the 30th or 31st day after the last new crescent. Since days begin at sunset, observers would have to keep the 30th day after the new crescent of Elul (6th month) as holy time, as they might see the new crescent that evening, though they would more commonly see it on the following evening.

For this reason, even in the land of Israel, Jews who follow the Pharisees’ traditions observe the Feast of Trumpets for two days back-to-back. Without making it a two-day celebration to ensure that the right day is observed, it is impossible to base the celebration of the Feast of Trumpets, the first day of the seventh month, on physical sighting of the new moon. Yet upon examining Leviticus 23 and Numbers 29, it is clear that the Feast of Trumpets must be observed for one day rather than two. This alone mandates a calculated calendar, in which the new moon day is determined in advance.

Another even more significant issue—the intercalary year—also requires a calendar calculated in advance. Intercalary years are those in which a 13th month is added. Twelve lunar months are equal to just over 354 days. A solar year is equal to just over 365 days. Using a calendar based only on 12 lunar months, this 11-day difference would cause the festivals to occur about a month earlier every three years in relation to the solar year and the seasons. Yet Leviticus 23:10–11 mandates that the priests should offer an omer of barley as a wave offering to God on the Sunday during the Days of Unleavened Bread, beginning the 50-day count to Pentecost. Clearly, this required that the first month, Abib or Nisan, could not be allowed to fall so early that no ripe grain would be available for the offering. This required the addition of a 13th month about every three years. But how was this addition determined?

Those who argue for direct physical sighting assert that the priests examined the grain crop each year before the end of the 12th month, and if they saw that it would not be ripe soon enough they added a 13th month to postpone the first month for about 30 days. The only alternative would be a regular cycle, calculated by the priests, to determine which years had 12 and which had 13 months. Is there biblical evidence as to the priests’ practice? There certainly is!

Acts 2, for instance, reminds us that Jews came to Jerusalem from all over the known world. If the decision regarding the 13th month were made a few weeks before Passover, how would Jews all over the world have known when to come to Jerusalem—or, for that matter, when to celebrate Passover in their own area? Significant numbers would either have been a month early or a month late! Remember, they could not call ahead on the telephone or check someone’s Web site! There was either an established pattern followed, or there would have been confusion among Jews throughout the Diaspora.

How could a calculated calendar have been figured anciently? In antiquity, man had only two ways of knowing the time of the new moon. One was by physical sighting of the crescent; the other was by calculation based upon the average time between conjunctions.

Some today wish to offer a substitute calendar based not on averages or observation, but on figures they have obtained from the National Aeronautics and Space Administration (NASA) or the U. S. Naval Observatory. These figures are derived from satellite observation and are supposed to be more exact than the averages from which the traditional Hebrew calendar was calculated.

Please understand, if there is one calendar that we can absolutely prove that Christ and the Apostolic Church DID NOT use, it is one based on satellite observation! The only calculated calendar that could possibly be used until after about 1968 was one based upon the average length of time between conjunctions. How were these averages obtained? Conjunctions of the sun, moon and earth are invisible except during a solar eclipse. Solar eclipses can occur only at the time of the new moon. Because the moon’s orbit is normally a few degrees above or below the plane of the earth-sun orbit, it is usually invisible when it is lined up in a direct line with the earth and sun—the time of conjunction. However, when the moon is on the exact plane of the earth-sun orbit, it will block the sun as it moves across, thereby making an eclipse of the sun.

A lunar eclipse, which can be seen on earth far more frequently than a solar eclipse, is the exact opposite of a solar eclipse. It can occur only at the time of the full moon, exactly halfway between conjunctions, when the moon is on the opposite side of the earth from the sun. By carefully recording the time of such eclipses and calculating the amount of time between them, the ancients were able to arrive at the average length of time between conjunctions. We speak of an “average” because the actual length can vary from month to month by a few hours, primarily because of the earth’s elliptical orbit around the sun and the resulting variation in the sun’s gravitational pull on the moon. While satellites may enable us to record conjunctions that are invisible from earth, ancient man could only calculate based upon averages.

Using eclipses, the average length of time between conjunctions of the sun, moon and earth can be calculated. This figure can then be used to calculate the new moon for years—and centuries—in advance. While the exact conjunction (invisible from earth anyway, except during a solar eclipse) may vary from the calculated molad (a Hebrew term referring to the “birth” of the moon) by up to a few hours, the calculations average out over time. And they are always very close; not accumulating lost or gained time even over many centuries.

The Hebrew calendar uses 29 days, 12 hours and 793 parts (an hour contains 1,080 parts) as the duration of the average lunar month. This works out to 29.53059 days in decimal form. According to the 15th edition of Encyclopedia Britannica, modern astronomers using satellites and computers have come up with the figure 29.530589—one one-millionth of a day difference!

How did the Hebrew calendar come to use such an accurate figure for the average length of the month? Some contend that they adopted their number from Babylonian or Greek astronomers. There is a problem with that theory, however. The figure used by the Greeks, Babylonians and Egyptians was not as accurate as that used by the Jews! If we grant that Israel of old borrowed the number from one of their ancient neighbors, then why did they modify it? How did they know to modify it just the right amount, making it more exact than the one used by anyone else? Remember, the figure used anciently to calculate the Hebrew calendar, 29.53059 days per month, was the same one used by NASA up through 1968 when satellite and computer technology allowed them to take the number out one more decimal place. How could an ancient Israelite mathematician have arrived at a more exact figure than his contemporaries? Exodus 31:1–11 shows that God’s Spirit empowered two men, Bezalel and Aholiab, to have special understanding and knowledge in being able to craft the items needed for the tabernacle. Did God’s Spirit also lead someone to have special ability for making astronomical calculations to fix the calendar? Clearly, someone did make a calculation that remained unsurpassed until the decade when the United States put a man on the moon!

Does the Bible support using eclipses to calculate the length of time from one new moon to another? It certainly does! Notice Genesis 1:14. God set the sun and the moon for signs and seasons. The Hebrew word for sign, ’ot, is a term that often refers to remarkable and dramatic signs. It is used in Exodus 4:8–9 for instance, to describe the dramatic wonders that God worked in ancient Egypt. There are no more dramatic signs designed into the interaction of the sun and moon than solar and lunar eclipses. These signs provide the basis of a calculated calendar.

Additionally, the heavenly bodies were for what the King James Version calls “seasons” and the Jewish Publication Society Version calls “appointed times.” The Hebrew word is mo’ed. This is the term used in Psalm 104:19 where we learn that God “has appointed the moon for seasons [mo’ed].” In other words, the phases of the moon determine the progression of the month. God’s annual festivals are either connected to the new moon at the beginning of the month or the full moon at the middle of the month.

Other biblical guidelines concern the seasonal timing of the Passover festival and the Feast of Tabernacles. We are told that Unleavened Bread is to be celebrated in the month of Abib, which means “green ears” (Exodus 23:15). From Leviticus 23 we also learn that once Israel entered the Promised Land there was to be a priestly ceremony involving the offering of the wave sheaf, the omer, on the Sunday during the Days of Unleavened Bread. The grain harvest could not begin until after that occasion. These stipulations require that Passover come in early spring.

Also, Exodus 34:22 refers to the Feast of Tabernacles as coming at the “end of the year” (Hebrew, tekufah). This term literally means a “circuit” or “revolution” of time—a cycle. In later Rabbinic Hebrew, tekufah became a technical term referring to the equinox and, by extension, to the season following. However, we must be careful about ascribing to Moses the technical usage of medieval rabbis. The term, used only four times in the Old Testament, was originally more general in its meaning. It is the term in 1 Samuel 1:20 that refers to the cycle of time between Hannah’s conception and the birth of Samuel. In 2 Chronicles 24:23, tekufah refers to the time of the year when Syria attacked Judah. The other place it is used is in Psalm 19:6 where it refers to the sun’s daily circuit across the heavens. Exodus 34:22 thus implies that the Feast of Tabernacles should occur when the cycle of the agricultural year is complete, about the time that summer gives way to fall. This point is made in a slightly different manner in Exodus 23:16. Again the King James Version translates that the Feast of Tabernacles is to occur at the “end of the year,” but this time uses a completely different word, meaning literally “the going out” of the year. It is the same term used in Exodus 13:8 to refer to Israel going out of Egypt. In other words, the Feast of Tabernacles comes at “the going out” of the harvest season of the agricultural year, right after the time when the harvest would be gathered into barns (that is why the term “Feast of Ingathering” is used), to protect it from the upcoming rainy season. This festival season of the seventh month was celebrated when summer was giving way to fall. To insist that tekufah could not refer to so much as one day before the autumnal equinox is to take a definition from the Talmud— not the Bible—and insist upon reading it back into scriptures written more than 16 centuries earlier.

We have seen that the Bible gives guidelines that require a calculated calendar, such as Trumpets being celebrated for one day and not two. It also shows that the interactions of the sun, moon and earth were to be factored in so that the numbering of the days of the month would be connected with the phases of the moon. We have also seen that celebration of the festivals is tied both to the beginning of the grain harvest and to the time when crops were to be gathered into barns at the end of summer. But are other aspects of the calendar, such as the so-called “postponements,” also necessary and based on biblical guidelines?

We must note that in the Hebrew calendar, the new moon of the seventh month (Tishri) is calculated, rather than the new moon of the first month (Abib). As this is the only new moon that is designated as holy time, it is also the new moon that is most essential to determine. The other holy days are figured from it. There is also an astronomical reason for this practice, since the time from the vernal equinox (spring) to the following autumnal equinox (fall) is about a week longer than from the autumnal equinox to the following vernal equinox.

The “postponements” are simply calendar adjustments that determine which day should be proclaimed as the first day of Tishri. While there are generally said to be four postponement rules, actually there are two primary ones. The other two are just logical extensions of the first two, to ensure that a year does not have too many or too few days.

The first rule we should look at states that if the calculated conjunction, the molad of Tishri, occurs after noon on a given day, the first day of the month is “postponed” until the following day. This rule results from the way time is measured on a round earth, and the length of time the moon takes to move out of conjunction and beyond the arc of the sun. After all, the term for “new moon” in scripture refers to the “repairing” of the moon. While a calculated calendar does not require that the visible crescent be sighted, it should at least be theoretically possible to sight that crescent. And it takes six hours past the conjunction before the moon has moved far enough beyond the sun’s arc to begin reflecting light once again—the “repairing” of the moon. Whether or not a reflection is actually seen is purely incidental, as the calendar is based upon the calculated averages. Clearly though, this postponement rule is not merely based upon a Pharisaic tradition, rather, it is mandated by Scripture and by astronomy.

The other main rule is that if the calculated molad of Tishri occurs on a Sunday, Wednesday or Friday, the first day of the month (which will be the Feast of Trumpets) is considered to begin on the following day, i.e., Monday, Thursday or Saturday. What is the scriptural basis for this? In Leviticus 23, where God first gave Moses a detailed list of His festivals, He explained that these days’ levels of sanctity fell into two categories. For six of these days—the first and seventh Day of Unleavened Bread, Pentecost, Trumpets, the first day of Tabernacles and the Eighth Day— Moses was to instruct Israel that “no servile work” be done. However, the weekly Sabbath and the Day of Atonement were different. On these two days, “no work whatsoever” was to be done. Clearly God placed these two days in a slightly different category than the others. Additionally, in describing Trumpets, the first day of Tabernacles, and the Last Great Day, the term shabbaton, translated “Sabbath,” was used. For the weekly Sabbath and the Day of Atonement a different descriptive term—shabbat shabbaton—was used, translated “a Sabbath of rest.”

Recognizing that God set the weekly Sabbath and the Day of Atonement apart in their level of sanctity, the Levitical priesthood sought to implement these instructions in proclaiming the festivals. They realized that the Day of Atonement, a shabbat shabbaton upon which “no work whatsoever” was to be done, should not be the preparation day for the weekly Sabbath (which would occur if the first of Tishri came on a Wednesday). Additionally, they avoided the weekly Sabbath being the preparation day for Atonement, which would happen if Tishri 1 fell on a Friday.

This practice also avoided the weekly Sabbath, shabbat shabbaton, being the preparation day for the other three fall holy days which were only shabbaton, (this would occur if Tishri 1 came on a Sunday). Note that according to Exodus 12:16, the first and seventh days of Unleavened Bread in the spring were in a different category; God had specifically approved the preparation of food on these days. And Pentecost, of course, always fell on Sunday as a result of God-ordained calculation.

Two other rules concerning postponements are really just logical extensions derived from the first two, regulating the number of days in a year so that the first of each month stays connected with the new moon.

The calendar adjustments regarding Tishri 1 are based upon instructions God gave to the Levitical priesthood through Moses in Leviticus 23. God made clear that two days—Sabbath and Atonement—had a special degree of sanctity, and based upon those instructions the priesthood sought to conform their celebrations to His wishes.

(Editorsnote: In the January/February 2001 Living Church News, John Ogwyn will explain in part 2 of this article who has the responsibility for keeping the calendar.)