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Exodus 12 · Leviticus 23, 25 · Esther · Nehemiah · Featured Study

The Hebrew Calendar

Israel counted its months by the moon, its years by two different starting lines, and kept the whole system anchored to spring with an extra month added when the arithmetic demanded it. This page walks the mechanism plainly: the new moon, the names Scripture actually gives the months, and the numbers behind the sabbatical and jubilee years, checked by hand.

The Lunar Month

the moon sets the calendar, and the trumpet announces it

1 SAMUEL 20:5 (ASV)

“Behold, to-morrow is the new moon, and I should not fail to sit with the king at meat: but let me go, that I may hide myself in the field unto the third day at even.”

PSALM 81:3 (ASV)

“Blow the trumpet at the new moon, At the full moon, on our feast-day.”

David expects a royal feast the next day for no reason beyond the new moon itself; Jonathan needs no further explanation. The Hebrew word for month, chodesh, is the same word used for the new moon: the month simply is the moon’s own cycle, counted.

Blow up the trumpet in the new moon. Announce the sacred month, the beginning of months, when the Lord brought his people out of the house of bondage. Clear and shrill let the summons be which calls all Israel to adore the Redeeming Lord. In the time appointed, on our solemn feast day. Obedience is to direct our worship, not whim and sentiment: God's appointment gives a solemnity to rites and times which no ceremonial pomp or hierarchical ordinance could confer.

Charles Spurgeon· The Treasury of David, Vol. 4, 1874Particular (Reformed) Baptist

Psa 81:3

  • ~29.5 days
    one lunar month
  • 12 months
    the ordinary year
  • ~354 days
    twelve lunar months, summed
  • ~11 days short
    of the sun's ~365-day year

What Scripture Calls the Months

two layers of names, and five names the Bible never uses

The early Hebrew names

Four names, all in 1 Kings, all naming a month in Solomon’s own Temple-building record.

Abib1st monthExodus 13:4
Ziv2nd month1 Kings 6:1
Ethanim7th month1 Kings 8:2
Bul8th month1 Kings 6:38

The Babylonian names, brought home from Exile

Seven names, every occurrence in a post-exilic book.

Nisan1st monthEsther 3:7
Sivan3rd monthEsther 8:9
Elul6th monthNehemiah 6:15
Kislev9th monthNehemiah 1:1
Tebeth10th monthEsther 2:16
Shebat11th monthZechariah 1:7
Adar12th monthEsther 3:7
The five names Scripture never usesIyar, Tammuz, Av, Tishri, Cheshvan

Five month names in common Jewish use today do not appear anywhere in the Hebrew Bible: Iyar (2nd month), Tammuz (4th), Av (5th), Tishri(7th, the month Scripture itself only ever calls Ethanim or “the seventh month”), and Cheshvan(8th, Scripture’s Bul). These surface first in post-biblical Jewish sources, the Mishnah and later, not in the canon. The grid below still uses the modern names, honestly marked, so a reader can navigate the calendar in the terms living Jewish practice actually uses.

Two Years, One Calendar

the religious year opens in spring; an older civil year turned in the fall

“This month shall be unto you the beginning of months: it shall be the first month of the year to you.” Exodus 12:2

Spoken the same month as the Exodus itself, this verse fixes Nisan (Abib) as month one of the religious year. Deuteronomy 16:1 repeats the command: “Observe the month of Abib, and keep the passover.”

this month shall be unto you the beginning of months--the first not only in order but in estimation. It had formerly been the seventh according to the reckoning of the civil year, which began in September, and continued unchanged, but it was thenceforth to stand first in the national religious year which began in March, April.

Jamieson, Fausset & Brown· Commentary Critical and Explanatory on the Whole Bible, 1871Reformed

Exo 12:2

Scripture leaves its own trace of that older reckoning. Twice the Torah calls the autumn harvest feast, Tabernacles, the end of the year:

EXODUS 23:16 (ASV)

“the feast of ingathering, at the end of the year, when thou gatherest in thy labors out of the field.”

EXODUS 34:22 (ASV)

“the feast of ingathering at the year’s end.”

That phrase only makes sense if a year was already being counted from a point that lands its own close in the fall. Jewish practice still keeps both reckonings side by side rather than resolving them into one: Rosh Hashanah, the new year most Jews mark today, falls on the first of Tishri, the seventh month by the religious count Exodus 12:2 commands. The Mishnah names the overlap directly, listing four separate new years for different purposes: months and festivals from Nisan, the tithing of cattle from Elul, and “the new year for years,” the agricultural and civil year, from Tishri (Rosh Hashanah 1:1). Named, dated, and placed: reception history, never MannaFest’s own confession.

The Extra Month

Adar II: post-biblical calendar mechanism, kept in seven years of nineteen

Twelve lunar months of about 29.5 days each run to roughly 354 days, about 11 days short of the sun’s own year of about 365 days. Left uncorrected, Nisan would drift earlier every year, and within a decade or two Passover would no longer fall in spring, breaking the very command that fixes it there (Deuteronomy 16:1, “Observe the month of Abib”).

Jewish practice, visible by the Second Temple period and later fixed into a calculated calendar credited to Hillel II in the fourth century AD, corrected the drift by adding a thirteenth month, Adar II (Adar Sheni), in seven of every nineteen years. The nineteen-year cycle works because nineteen solar years and 235 lunar months land within about half a day of each other, the same cycle used in other ancient calendars. This is a described mechanism of post-biblical Jewish practice, not a scriptural institution; Scripture commands that Passover be kept in the month of Abib, but nowhere legislates the intercalation method itself.

  • 354 days
    twelve lunar months, summed
  • 365 days
    one solar year, roughly
  • 7 of 19 years
    carry the extra month
  • 19 years ≈ 235 months
    the cycle's own check

The Year at a Glance

twelve months, their season, and what falls on each

Nisanmonth 1

early name: Abib (Exodus 13:4)

Spring (Mar-Apr)

Iyarmonth 2

early name: Ziv (1 Kings 6:1)

Spring (Apr-May)

Pesach Sheni (Num 9:1-14)
Sivanmonth 3

Late spring (May-Jun)

Tammuzmonth 4

Summer (Jun-Jul)

no feast on the calendar
Avmonth 5

Summer (Jul-Aug)

no feast on the calendar
Elulmonth 6

Late summer (Aug-Sep)

no feast on the calendar
Tishrimonth 7

early name: Ethanim (1 Kings 8:2)

Autumn (Sep-Oct)

Cheshvanmonth 8

early name: Bul (1 Kings 6:38)

Autumn (Oct-Nov)

no feast on the calendar
Kislevmonth 9

Late autumn (Nov-Dec)

Tebethmonth 10

Winter (Dec-Jan)

no feast on the calendar
Shebatmonth 11

Winter (Jan-Feb)

no feast on the calendar
Adarmonth 12

Late winter (Feb-Mar)

Adar II (Adar Sheni), a thirteenth month, is inserted after Shebat and before Nisan in seven of every nineteen years (see “The Extra Month” above). Post-biblical calendar practice, not a named Scripture month.

Name not found anywhere in the Hebrew Bible; known only from post-biblical Jewish tradition.

The Sabbatical and Jubilee Cycles

Leviticus 25: the seventh year's rest, the fiftieth year's liberty, the arithmetic checked

“Six years thou shalt sow thy field... but in the seventh year shall be a sabbath of solemn rest for the land, a sabbath unto Jehovah.” Leviticus 25:3-4

Every seventh year the land itself rests: no sowing, no pruning, no organized harvest. What grows on its own feeds the household, the servants, and the hired hand alike (25:5-6).

The institution of the sabbatical year was designed, 1. To shew what a plentiful land that was, into which God was bringing them, that so numerous a people could have rich maintenance out of the products of so small a country, without foreign trade, and yet could spare the increase of every seventh year.

John Wesley· Explanatory Notes upon the Old Testament, 1765Evangelical

Exo 23:10

“And thou shalt number seven sabbaths of years unto thee, seven times seven years; and there shall be unto thee the days of seven sabbaths of years, even forty and nine years.” Leviticus 25:8

Seven sabbaths of years: 7 × 7 = 49, stated in the text and checked. Two verses later the trumpet sounds on the Day of Atonement to open what the text calls the fiftieth year:

“And ye shall hallow the fiftieth year, and proclaim liberty throughout the land unto all the inhabitants thereof.” Leviticus 25:10

The count (49 sabbatical years, then a 50th jubilee) is real arithmetic the text itself states; whether the 50th year is a fresh year after the 49th, or an inclusive count that folds the end of one 49-year span into the start of the next, is a question the commentators work through directly rather than one this page settles for the reader.

Thou shalt number seven Sabbaths of years - This seems to state that the jubilee was to be celebrated on the forty-ninth year; but in Lev 25:10 and Lev 25:11 it is said, Ye shall hallow the fiftieth year, and, A jubilee shall this fiftieth year be. Probably in this verse Moses either includes the preceding jubilee, and thus with the forty-ninth makes up the number fifty; or he speaks of proclaiming the jubilee on the forty-ninth, and celebrating it on the fiftieth year current.

Adam Clarke· Commentary on the Bible, 1832Methodist

Lev 25:8

The theology of the jubilee (liberty, the land’s return, the typology it carries) belongs to its own page. Jubilee: the theology of the fiftieth year → The weekly sabbath this whole numbering echoes is its own study too. Sabbath Rest →

The Voices

with the work named

Charles Spurgeon

The Treasury of David, Vol. 4 (1874) · public domain

Reads Psalm 81:3's trumpet at the new moon as obedience giving solemnity to worship: God's own appointed times, not human sentiment, set the calendar's rhythm.

Jamieson, Fausset & Brown

Commentary Critical and Explanatory on the Whole Bible (1871) · public domain

States the two reckonings side by side at Exodus 12:2: the civil year beginning in September stood unchanged even as the new religious year, beginning in spring, was commanded first place.

John Wesley

Explanatory Notes upon the Old Testament (1765) · public domain

On Exodus 23:10, reads the sabbatical year's design as proof of the land's own richness: a nation that could rest its fields one year in seven and still be fed.

Adam Clarke

Commentary on the Bible (1832) · public domain

Works through Leviticus 25:8's own arithmetic tension directly: whether the jubilee lands on the counted forty-ninth year or the fiftieth, and how the text can be read either way.

Marcus Brown's own commentary leads above all; within a tier, all voices are equal.

Drafted from the 2026-08-20 Hebrew Calendar research brief. Scripture quoted from the American Standard Version, verified against the site's resident verses table. The Mishnah's four new years (Rosh Hashanah 1:1) is reused from the pre-verified citation in src/lib/hebraic/feasts.ts. Spurgeon, The Treasury of David, Vol. 4 (1874, PD); Jamieson, Fausset & Brown, Commentary Critical and Explanatory on the Whole Bible (1871, PD); Wesley, Explanatory Notes upon the Old Testament (1765, PD); Clarke, Commentary on the Bible (1832, PD). Scripture ASV. Every cited work: the sources registry →