UPDATED 05 MARCH, 2015
What do you think of the Lunar Sabbath theory?
A lunar Sabbath is not practiced by anyone in today’s Messianic Judaism or the One Law/One Torah sub-movement, but it may be favored by people here and there on the fringes of the Two-House sub-movement. Generally speaking, those who have rejected the mainstream Jewish calendar used by the Synagogue today, and the vast majority of Messianic Jews—in favor of their own calendar—are those who are open to later questioning the placement of the seventh-day Sabbath on the day of the week known on our secular calendar as Saturday. The basic argument in favor of a Lunar Sabbath is: the Jews were wrong about the calendar, and so they must be wrong about the Sabbath. The Lunar Sabbath theory posits that with the beginning of a new month via the New Moon, all one has to do is count seven days to the Sabbath, seven days to the next Sabbath, and so on. This would mean that the Sabbath day could actually be on any day of the secular week.
There has been very strong criticism issued against the Lunar Sabbath theory, from various Seventh-Day Adventists, as well as from those who teach on the Jewish Roots of Christianity. While there is fertile ground for adoption of a Lunar Sabbath in the fringe sectors of the Two-House sub-movement, the Sacred Name Only movement, and among various others—the Lunar Sabbath theory has actually received broad rejection from most Sacred Name Only groups.
Since hearing about the Lunar Sabbath theory in the mid-2000s, Outreach Israel Ministries and Messianic Apologetics have widely dismissed it. Academic resources discussing the history of Sabbath development, while widely recognizing the dismissal of the seventh-day Sabbath by the emerging Christianity of the Second and Third Centuries C.E., do not argue that the Ancient Israelites observed a seventh-day Sabbath based off of the determination of the New Moon.
The Lunar Sabbath theory does not have any coherent logic to it, given the Biblical prescription of how the Sabbath is to take place every seven days. What if there is a New Moon sighted on the sixth day of one’s counting cycle to the Sabbath, and the counting cycle to the Sabbath has to be reinitiated? This would mean that it is possible for there not to be a Sabbath day of rest for a period of thirteen days. If a lunar month were exactly twenty-eight days, then there might be some reason to consider a kind of Lunar Sabbath. But, the Moon’s cycle is twenty-nine-and-a-half days.
Both liberal and conservative Bible scholarship are widely agreed that a Lunar Sabbath is not at all what is witnessed within the Hebrew Scriptures, and are most dismissive of such a proposition:
- IDBSup (broadly liberal): “The appearance of the new moon marks the first day of the lunar month. The full moon usually occurs on the fourteenth or fifteenth day, and the dark of the moon follows on the twenth-eighth or twenty-ninth. Thus, seven-day intervals such as the first, eighth, fifteenth, twenty-second, and twenty-ninth of the month or the first, seventh, fourteenth, twenty-first, and twenty-eighth of the month can be correlated to lunar phases. However, if the sabbath originated as a seventh-day interval fixed by the appearance of the new moon, it could not have recurred every seventh day. A ‘lunar’ sabbath would have been recycled each month, because a lunar month is not evenly divisible by seven days. Yet the oldest biblical traditions suggest that the sabbath did occur every seven days (Exod. 23:12; 34:21). Thus, the sabbath was ordinarily out of phase with the moon.”
- ISBE (broadly conservative): “A [particular] theory proposes an ancient Arabic origin [for the Sabbath]…In their worship of the moon the ancient Arabs supposedly paid particular attention to the four monthly phases of the moon, i.e., where the moon ‘sat.’ The Arabic word for ‘sit,’ ṯabat, supposedly became Akk. šabattu and later Heb. šabbāṯ. Regular human rest at approximately seven day intervals thus would be patterned after the moon’s rest…[T]he etymology is suspect. Moreover, this theory shares the same weakness as any lunar theory, namely, that a regularly recurring seventh-day sabbath will almost always be out of phase with the moon, since the lunar month contains twenty-nine days instead of twenty-eight.”
In his famed work, The Sabbath, Abraham Joshua Heschel summarizes the widespread Jewish theological view of how while the new month in the Torah begins with the New Moon, that the Sabbath is something independent from the New Moon:
“While the festivals celebrate events that happened in time, the date of the month assigned for each festival in the calendar is determined by the life in nature. Passover and the Feast of Booths, for example, coincide with the full moon, and the date of all festivals is a day in the month, and the month is a reflection of what goes on periodically in the realm of nature, since the Jewish month begins with the new moon, with the reappearance of the lunar crescent in the evening sky. In contrast, the Sabbath is entirely independent of the month and unrelated to the moon. Its date is not determined by any event in nature, such as the new moon, but by the act of creation. Thus the essence of the Sabbath is completely detached from the world of space.”
In an endnote, Heschel indicates how, “The Babylonian seventh day was observed on every seventh day of the lunar month.” Generally speaking, those who have wished to associate the Israelite Sabbath with some kind of lunar cycle, have done so with the intention of trying to establish some kind of extra-Biblical, or even Mesopotamian pagan origin, for the Sabbath.
In 2005, a brief piece entitled “Which Day is the 7th?” appearing in Messiah Magazine, published by the popular ministry First Fruits of Zion, was widely and properly dismissive of the Lunar Sabbath theory:
How can we prove that Sabbath occurs on Saturday? I understand God commanded us to rest on the seventh day. But which day of the week is the seventh? I know the biblical new month starts with the new moon. Is the new moon always on the same day of the week? I would very much appreciate your help with this. I am a Bible teacher and we meet on Friday nights and study Torah. Any help is appreciated.
Thanks for asking about this. Your question is a common one. Many people ask the same thing, and there are some errant teachings floating around that suggest the Sabbath should be counted as the seventh day from the New Moon instead of the seventh day of the week. This has a lot of people confused.
The New Moon can appear on any day of the week. The days of the month on the lunar calendar are counted from the New Moon, but the days of the week are not. This means that any day can be the first day of the month, but it does not mean that any day can be the first day of the week. The Sabbath is not, and never has been counted from the New Moon. The seven-day cycle of the week is completely independent of the New Moon.
Bad information about how to reckon the Sabbath, and festivals and the calendar arises primarily from an unhealthy suspicion of Jewish tradition. For some reason, many Gentile believers assume that they know how to keep Torah better than the people who received the Torah.
How can we know that Saturday is the Sabbath? The answer is the Jewish people. There is an unbroken chain of Jewish people reaching all the way back to Mount Sinai when the Sabbath was given. It is certainly possible for you or I to forget what day of the week it is, but a whole community will not forget the day of the week. Day after day, week after week, the Sabbath has been preserved by the collective identity of Israel. The weekly cycle of Sabbath keeping is continuous.
There has never been a community of Torah keepers that supposed the seventh day was some day other than Saturday.
We know that Yeshua and the Apostles regarded the same weekly 24-hour period as Sabbath along with the rest of Judaism. Unlike in Christianity, in Judaism there is no break in the continuity of keeping the Sabbath. Judaism remains a living link through time with the days of the Apostles.
It is true that both the Jewish calendar and the civil, Julian calendar have had a few revisions and corrections from time to time. But those changes did not affect the weekday. The seven-day week has been used at least since the days of Moses and certainly since the days of the Master. Day after day, week after week, the Jewish people have preserved the day of the Sabbath ever since God commanded Israel to keep it. May God bless you in your efforts to teach His Word.
 Terry Heagy, The Lunar Sabbath Conspiracy (GATE Publishing, 2011).
 Bruce R. Booker, The Lunacy of the Lunar Sabbath (Author, 2008).
 B.E. Shafer, “Sabbath,” in IDBSup, pp 760-761.
 J.C. McCann, Jr., “Sabbath,” in ISBE, 4:248.
 Abraham Joshua Heschel, The Sabbath (New York: Farrar, Straus and Giroux, 1951), 10.
 Ibid, en#11.
 Cf. Gerhard F. Hasel, “Sabbath,” in ABD, 5:850-851.
 “Which Day is the 7th?” Messiah Magazine Issue 87, Devarim 5765 (2005):33.