There have been many “biblical calendars” but the seven listed below are the ones currently utilized by almost all of the Sabbatarian churches observing the biblical annual holy days and the three annual festivals.
1] Jewish (Hebrew) Calendar
New Year’s Day (Rosh Hashanah) is the 1st day of the 7th month (Tishri), which is because Jewish tradition declares that “Adam and Eve were created on that day.” All the annual holy days and festivals are calculated from this day, not from the 1st day of the 1st month.
The 1st day of the 7th month (Tishri) is the day of the Molad Emtzai (conjunction), unless one of the four postponement rules apply. In 2025 a mathematical postponement rule pushes Rosh Hashanah one day forward to Tuesday, the 23rd of September 2025.
[2] Jewish (Hebrew) Calendar of the Worldwide Church of God
The Church of God 7th Day has been observing the Last Supper/Passover annually since the 1870s, using the Jewish calendar to ascertain the date.
Two figures came to prominence in the 1930s, promoting the observance of all the biblical annual holy days and festivals : Clarence Dodd, who founded The Faith Magazine, which brought many people into the Sacred Names Movement, and Herbert Armstrong, founder of a radio ministry, the Radio (renamed in 1968 Worldwide) Church of God. The two men corresponded regularly (though never met), until their relationship ended in 1940 over how to calculate Passover.
Herbert Armstrong made some changes to the Jewish Calendar :
• He believed New Year’s Day to be the 1st day of the 1st month, and did not understand that all the dates in the Jewish Calendar are calculated from the 1st day of the 7th month, and thus unknowingly followed the Jewish method.
• The Lord’s Supper/Passover must be observed on the evening of the 14th of the 1st month, and not on the 15th like the Jews.
It must not be observed with a supper, as Jesus and his disciples did, nor a seder meal as the Jews do, but must follow the Protestant tradition of a very sombre ceremony, eating only a small piece of unleavened bread and drinking a few sips of wine.
• Instead of observing the Festival of Weeks (which the Jews call ‘Shavuot’) on the 6th of Sivan, 50 days must be counted from the Sunday within the Festival of Unleavened Bread, Monday being the 1st day of the count, so that ‘Pentecost’ would be on a Monday. In 1974 Herbert Armstrong was persuaded by leading ministers that counting in Hebrew was inclusive, meaning that Sunday should be the 1st day of the count, and therefore from that year Pentecost was observed on a Sunday.
[3] Day of the astronomical new moon [29th of March 2025],
nearest to the vernal equinox [20th of March 2025].
[4] Day of the appearance of the crescent new moon [31st of March 2025],
nearest to the vernal equinox [20th of March 2025].
[5] Day of the astronomical new moon [29th of March 2025],
following the vernal equinox [20th of March 2025].
[6] Day of the appearance of the crescent new moon [31st of March 2025],
following the vernal equinox [20th of March 2025].
[7] Day of the appearance of the crescent new moon in the month that the barley in Israel will be ready for harvesting by the Sunday after Passover (Leviticus 23:10-12). [31st of March 2025]
The date of the crescent new moons is confirmed by sighting the new moon in the area of Jerusalem.
The dates for the vernal equinox and the astronomical new moon are based on Jerusalem times.
In the table below, the 3 annual festivals (Exodus 23:14-16) are printed in bold green, and the 7 annual holy days are in bold red. The red numbers along the top row are the 7 most popular biblical calendars.
|
[1] |
[2] |
[3] |
[4] [7] |
[5] |
[6] |
|
|
New Year’s Day |
Tue-Wed |
Sun |
Sat |
Mon |
Sat |
Mon |
|
Seder/Passover/ |
Sun |
Sat |
Fri |
Sun |
Fri |
Sun |
|
Festival of (Passover) |
April |
April |
April |
April |
April |
April |
|
First Day of |
Sun |
Sun |
Sat |
Mon |
Sat |
Mon |
|
Last Day of |
Sun |
Sat |
Fri. |
Sun |
Fri |
Sun |
|
Festival of Weeks |
Mon-Tue |
Sun. |
Sun. |
Sun. |
Sun. |
Sun. |
|
Day of Trumpets |
Tue-Wed |
Tue |
Mon |
Wed |
Mon |
Wed |
|
Day of Atonement |
Thu |
Thu |
Wed |
Fri |
Wed |
Fri |
|
Sukkot – Festival |
Oct.7- |
Oct.7-Oct.13 |
Oct.6 – |
Oct.8 – |
Oct.6- |
Oct.8 – |
|
1st Day of |
Tue |
Tue |
Mon |
Wed |
Mon |
Wed |
|
|
Tue-Wed |
Tue |
Mon |
Wed |
Mon |
Wed |
Why are these seven calendars the ones most utilized by Church of God groups? What are the biblical justifications for them?
“The history of the Jewish calendar may be divided into three periods – the Scriptural, the Talmudic, and the post-Talmudic. The first rested purely on the observation of the sun and the moon, the second on observation and reckoning, and the third entirely on reckoning.”
(The Jewish Encyclopedia : History of Calendar)
According to the Mishnah – a collection of 63 tractates, divided into 6 orders, one of them being the Mo’edim (appointed times), the “Scriptural Calendar” [7] was observed at the Second Temple, and the Talmudim (completed c.500AD) show that it continued to be observed into the 5th century AD.
“The calendar of the Mishnah is discussed and debated in detail in both the Palestinian and the Babylonian Talmudim … The fact that no other calendar system is ever referred to in the Talmudim may be regarded as significant. In the absence of evidence to the contrary, it is reasonable to assume that the Mishnaic system was perpetuated well into the Amoraic period (third to fifth centuries).” (Sacha Stern, ibid, p.181)
The first month of the year was when the barley (the early summer grain crop) would be ready for harvesting by the Sunday after Passover (Leviticus 23:10-12).
If there were doubt as to the time of this harvest, the Sanhedrin would consider secondary signs – the sufficiency of lambs for Passover and signs in nature that winter was ending.
“This month shall be unto you the beginning of months: it shall be the first month of the year to you … In the tenth day of this month they shall take to them every man a lamb.” (Exodus 12:2-3)
For, lo, the winter is past; The rain is over and gone; The flowers appear on the earth; The time of the singing of birds is come, And the voice of the turtle-dove is heard in our land; The fig-tree ripeneth her green figs, And the vines are in blossom; They give forth their fragrance. (Song of Solomon 2:11-13)
How was the 1st day of each month determined?
“The beginning of the months were determined by direct observation of the new moon. Then those beginning of months (Rosh Hodesh) were sanctified and announced by the Sanhedrin, the Supreme Court in Jerusalem, after witnesses testified that they had seen the new crescent and after their testimony had been thoroughly examined, confirmed by calculation and duly accepted.” (Arthur Spier, The Comprehensive Hebrew Calendar, p.1)
Witnesses could come from outside Jerusalem, but travel overnight by foot or donkey limited the distance.
After the destruction of the Temple, how did the Palestinian court notify the scattered Jewish communities in the Diaspora of its decisions on the new year and new moons?
… “the dependence of Diaspora communities on the calendrical decisions of the Palestinian rabbinic court. This assumption is based on contemporary rabbinic sources, but these reflect rabbinic wishful thinking rather than historical reality. All the evidence suggests, in fact, that Diaspora communities took charge of their own calendar, without ever referring to Palestinian calendrical authority. (Sacha Stern, ibid., p.100)
By far the largest Jewish community in the Diaspora was in Babylonia, which remained loyal to the Palestinian court, because the Babylonian rabbis observed the Jewish Oral Law, which required the calendar to be declared from Palestine. As Babylon is nearly a thousand miles away from Jerusalem, torches were lit along the route to Babylon when the new moon had been sighted, which was critical for the new moon of the seventh month, but not always successful.
“At the time of the Second Temple, when the Sanhedrin announced the beginning of the months on the basis of observation, the communities living far from the seat of the court could not be reached in time by its messengers. Those communities, in doubt about the day of the New Moon and the festivals, established the custom of celebrating an additional day for each of the major holidays. Thus they were certain to observe the festivals at the same time as their brethren in Israel, on the days sanctified by the Sanhedrin. Whenever the Torah had prescribed one day of holy convocation and prohibition of work, they celebrated two days – except on Yom Kippur to avoid two successive days of fasting. Its observance … (by tradition) became a generally accepted law.” (Arthur Spier, The Comprehensive Hebrew Calendar, p.11)
There followed a lot of discussion among the rabbis in Babylon, recorded in the Babylonian Talmud (ended c.500AD), on introducing fixed rules that would limit the Palestinian calendar court as to when the calendar year and months could start.
This was the end for the “Scriptural Calendar” [7] – although a group known as the Karaites continued to observe it as best they could – and they still do today, but their numbers are now much reduced.
A rule was agreed during the Talmudic period that the 1st month should begin at the new moon nearest the spring equinox. The biblical justification for doing so was dependent upon interpreting the Hebrew word tequfah in Exodus 34:22 to mean equinox.
A further rule that appears to date from the Amoraic period is that of the equinox. Although the equinox is mentioned already in the Tosefta, it only serves as one of a few criteria involved in the intercalation (see section 4.1.2). The rule that emerges in the Amoraic period is that intercalations can and should be made on the sole basis of the equinox.
The rule of the equinox is attested in a single passage in the Babylonian Talmud (Rosh ha-Shanah 21a) … implies that 15 Nisan, the first day of Unleavened bread, cannot occur before the vernal equinox. In this recension, the term aviv is treated as synonymous with tequfah (equinox). (Sacha Stern, ibid, p.184)
Tequfah (Strong’s H8622): a revolution, i.e. (of the sun) course, (of time) lapse).
This Hebrew word is found in 4 verses:
“You are to observe the Festival of Weeks, the first fruits of the wheat harvest, and the Festival of Tabernacles at the turn of the year.” (Exodus 34:22)
“Turn of the year” here refers to the turn of the season from Summer to Winter. (The seasons of Spring and Autumn are not found in the Bible.)
‘And it happened, at the turn of the year, that the army of Syria came up against him…’ (2 Chronicles 24:23)
Armies generally went on the move when the winter rains had ended.
‘And it happened when the time had come around, Hannah conceived and bore a son’ (1 Samuel 1:20).
‘… his going forth from the end of the heavens, and his orbit to their ends’ (Psalm 19:6)
Those keeping calendars [3] and [4] observe the Passover/Lord’s Supper at the first full moon after the vernal equinox, but [5] and [6] require the new moon to be after the equinox, so they sometimes observe it one month later, as was the case in 2024.
As it was not possible to calculate the equinoxes accurately in ancient times, the Jewish calendar utilizes a 19-year time cycle, with a 13th month added in 7 of the years. The Jewish calendar was originally aligned with the spring equinox and calendar [3]. This time cycle is not, however, exactly synchronized with the length of the solar years, so that Passover and the festivals have been gradually slipping later in the year, and are now occasionally, as in 2024, observed at the same time as calendar [6]. The Jews are aware of the problem, and intend to update the calendar, but the authority to do this requires the establishment of an official Sanhedrin in Jerusalem.
The Scriptural Jewish Calendar [7] has enjoyed a revival in the Internet Age, as reports of the Aviv Barley and New Moon Sightings can now be received instantly.
Is the new moon the conjunction or the sighting of the crescent new moon?
The Sanhedrin website states that sighting the new moon is required by Jewish law. The Jews therefore intend to return to sighting the new moon as soon as the current Sanhedrin achieves official status and thus will have the authority to change from the calculated calendar:
Until then tradition requires the Jews to adhere to the calculated calendar.
“A special court has been established to accept evidence concerning the sighting of the New Moon, as required by Jewish Law. This court is made up of various justices who are assembled to hear evidence as the opportunity permits. The purpose of the court is to increase awareness, develop skills, and resolve halachic issues that arise when determining the Jewish Calendar according to testimony by witnesses. At this point there is no intention to supercede the mathematical calendar currently in use and fix the calendar on the basis of the testimony, such a step should be unacceptable to the public and spiritual leadership. Nevertheless, witnesses appear before the court and are investigated with precision according to what they saw. Sometimes the witnesses may also bring photographic evidence to support their testimony. Evidence is already being collected by the yiresh shomaim volunteers throughout the Land of Israel, with the intention that testimony can be presented before the court in a full legal fashion when the peoples’ hearts are ready for it.”
7th Day Churches of God 