God's Biblical Calendar: Moons, Months and Appointed Times
Netivyah International
God's calendar in the Bible is set by the lights He placed in the sky. Each month begins with the new moon, and the years are kept in step with the sun's seasons so that the feasts land at the right harvests in the land of Israel. Scripture preserves four early Hebrew month names: Aviv, Ziv, Ethanim and Bul. The names Jewish people use today (Nisan, Iyar, Tishrei, Cheshvan and the rest) came back with the exiles from Babylon.
That is the short answer. The longer one is worth the time, because these dates are more than squares on a wall calendar. They are meetings.
Written into creation on the fourth day
Before there was a man or woman to keep a calendar, God set one in motion.
"Then God said, 'Let there be lights in the firmament of the heavens to divide the day from the night; and let them be for signs and seasons, and for days and years.'" (Genesis 1:14)
The word translated "seasons" is mo'adim, the plural of mo'ed (מועד). It does not mean winter and summer. It means an appointed time, an appointed place, a set meeting. The same word gives the tabernacle its name, the Ohel Mo'ed, the Tent of Meeting. The tabernacle was the place where God met Israel. His calendar is the time.
Psalm 104:19 uses the same word: "He appointed the moon for seasons; the sun knows its going down." The moon is the hand on God's clock.
You can see the meeting idea plainly in the three pilgrimage feasts:
"Three times a year all your males shall appear before the Lord your God in the place which He chooses: at the Feast of Unleavened Bread, at the Feast of Weeks, and at the Feast of Tabernacles; and they shall not appear before the Lord empty-handed." (Deuteronomy 16:16)
People came up to Jerusalem carrying part of what the land had produced. For an overview of each appointed time, see The Basics of the Mo'adim.
God's calendar and man's calendar
The calendar most of the world uses, the Gregorian, follows the sun alone. Its months have nothing to do with the moon. The Islamic calendar follows the moon alone. Twelve lunar months come to about 354 days, so its holidays slide backward through the seasons year after year.
The biblical calendar is lunisolar. It holds both. A month (Hebrew yerach, ירח, literally "moon") begins when the new moon appears. But twelve moons fall about eleven days short of a solar year, and the Torah does not allow the feasts to wander. Passover must fall in Aviv, the month of ripening barley (Deuteronomy 16:1). So from time to time a thirteenth month has to be added.
In the Second Temple period this was done by observation. The Mishnah, in tractate Rosh Hashanah, describes witnesses coming to the court in Jerusalem to testify that they had seen the new moon. Today the Jewish calendar is calculated in advance. It adds seven leap months over a 19-year cycle by repeating the month of Adar, which is why some years have an Adar II. We explain how that fixed calendar came about in The Hillel II Calendar and Double Torah Portions.
The old month names: Aviv, Ziv, Ethanim and Bul
The earlier books of the Bible usually number the months ("the second month," "the seventh month"). Only four of their names survive:
- Aviv (first month, March to April). It means "spring," and is the word used in Exodus 9:31 for barley in the ear. It is the month of the Exodus (Exodus 13:4; 23:15).
- Ziv (second month, April to May). It means "light" or "brightness." Solomon began building the Temple in Ziv (1 Kings 6:1, 37).
- Ethanim (seventh month, September to October). It is usually understood as "permanent" or "ever-flowing." The Temple was dedicated at the feast in Ethanim (1 Kings 8:2).
- Bul (eighth month, October to November). Its meaning is less certain. The Temple was finished in Bul (1 Kings 6:38).
So if you searched "month of Ziv and Bul," 1 Kings 6 is where you met them. The Temple took seven years, from Ziv of one year to Bul of another.
Where Nisan, Iyar and Tishrei came from
The twelve months Jewish people use today are Nisan, Iyar, Sivan, Tammuz, Av, Elul, Tishrei, Cheshvan, Kislev, Tevet, Shevat and Adar. These are Babylonian names. They begin appearing in the books written from the exile onward: Nisan in Esther 3:7 and Nehemiah 2:1, Kislev in Nehemiah 1:1, Shevat in Zechariah 1:7.
The old names line up with the new ones. Aviv is Nisan, Ziv is Iyar, Ethanim is Tishrei, and Bul is Cheshvan.
Two ways to begin a year
In Exodus 12:2 God tells Moses that the month of the Exodus is "the beginning of months." By that count, the year starts in spring.
Yet Jewish people celebrate the new year in the fall, on the first of Tishrei. The Torah calls this day a memorial of blowing trumpets (Leviticus 23:24), and today it is known as Rosh Hashanah, "head of the year." The name Tishrei itself comes from the Akkadian tašrītu, "beginning." The Mishnah (Rosh Hashanah 1:1) counts the first of Tishrei as the new year for counting years, sabbatical years and jubilees.
The fall turning point is old. Exodus 23:16 places the Feast of Ingathering, Chag ha-Asif (חג האסיף), "at the end of the year." That is the Torah's name for Sukkot. Anyone who lives in Israel sees the olive harvest around October, and the farming year really does roll over there.
A farmer's calendar from Gezer
One of the oldest Hebrew inscriptions we have, the Gezer Calendar, dates to the 10th century BC. It was found at Gezer in the foothills west of Jerusalem, and it divides the year by farm work:
- Two months of ingathering (olives)
- Two months of sowing (grain)
- Two months of late sowing (legumes and vegetables)
- A month of hoeing (for hay)
- A month of barley harvest
- A month of harvesting (wheat) and measuring
- Two months of grape harvest
- A month of summer fruit
Notice that it opens with ingathering, in the fall. Scholars still debate what the inscription was for. Some see a school exercise, some a song, others a record for collecting taxes. Whatever its purpose, the farmers of Israel did not need it to know when to plant. They learned that in the field.
The neighbors of ancient Israel believed rain and harvest depended on pleasing a crowd of gods: sun, moon, river and wind. The Torah says something very different. Rain comes from the one God, in response to obedience: "I will give you the rain for your land in its season, the early rain and the latter rain, that you may gather in your grain, your new wine, and your oil" (Deuteronomy 11:14). Wisdom does not begin with experience. "The fear of the LORD is the beginning of wisdom" (Proverbs 9:10).
What the appointed times point to
The feasts remember what God has done, and they lean toward what He will do.
Passover recalls the Exodus, and it is the season of Yeshua's (Jesus') death and resurrection. Jewish tradition holds that the Torah was given at Sinai at the time of Shavuot, the Feast of Weeks. On that same feast, in Acts 2, the Holy Spirit was poured out on Yeshua's disciples in Jerusalem.
In the fall, the Feast of Trumpets and Yom Kippur call God's people to repentance and remind them of judgment. You can read more in Hearing the Shofar on the Feast of Trumpets.
Then comes Sukkot, the seven-day Feast of Tabernacles (Leviticus 23:34). It looks ahead to the day John heard announced:
"And I heard a loud voice from heaven saying, 'Behold, the tabernacle of God is with men, and He will dwell with them, and they shall be His people. God Himself will be with them and be their God.'" (Revelation 21:3)
In Hebrew thinking, that tabernacle is a sukkah (סוכה).
The order matters. Redemption, then Torah and Spirit, then a call to repent, then God dwelling with His people. Yeshua told His disciples to read the signs of the times the way a farmer reads a fig tree. He spoke of the sun darkened and the moon withholding its light (Matthew 24:29), and then said:
"Now learn this parable from the fig tree: When its branch has already become tender and puts forth leaves, you know that summer is near. So you also, when you see all these things, know that it is near, at the doors!" (Matthew 24:32-33)
How Jewish families mark the months today
The new month, Rosh Chodesh, is a small holiday of its own. Numbers 10:10 tells Israel to blow trumpets at the beginnings of their months, over the offerings, as a reminder before God.
In synagogues today, the coming new month is announced on the Shabbat before it, with a prayer for a good month. On Rosh Chodesh itself, part of the Hallel psalms is added to the morning prayers. When the previous month had thirty days, Rosh Chodesh is kept for two days. For one example of how a single month carries its own themes, see Rosh Chodesh Tammuz.
Marking the new month at home
You do not have to give up your wall calendar, leave your church or become Jewish to live by this rhythm. Look up the date of the next Rosh Chodesh. That evening, step outside with your family and find the moon. Read Psalm 104:19 together, then take five minutes for three things:
- Look back. Name one way God provided for your household this past month.
- Give something. Israel was not to appear before God empty-handed. Choose one gift for the month ahead, of money, time or help to someone in need.
- Look ahead. Pray Proverbs 3:5 over the coming weeks: "Trust in the LORD with all your heart, and lean not on your own understanding."
Then sit with one question until the next new moon: if the Lord came to meet you at His next appointed time, what would you have in your hands to bring Him?
Questions people ask
What is the month of Ziv in the Bible?
Ziv is the second month of the biblical year, around April to May. The name means "light" or "brightness." Solomon began building the Temple in the month of Ziv (1 Kings 6:1, 37). Today the same month is called Iyar.
What are the months of Ziv and Bul?
Both names appear in 1 Kings 6. Ziv is the second month (April to May), when Temple construction began. Bul is the eighth month (October to November), when it was finished seven years later (1 Kings 6:38). Their modern Jewish names are Iyar and Cheshvan.
What are the biblical month names?
Only four early Hebrew names survive in Scripture: Aviv (first month), Ziv (second), Ethanim (seventh) and Bul (eighth). The later books use Babylonian names, and the Jewish calendar still uses them today. These are Nisan, Iyar, Sivan, Tammuz, Av, Elul, Tishrei, Cheshvan, Kislev, Tevet, Shevat and Adar.
What is the difference between God's calendar and man's calendar?
The Gregorian calendar follows the sun only, and the Islamic calendar follows the moon only. The biblical calendar follows both. Months begin with the new moon, and an extra month is added from time to time so that Passover stays in spring and the harvest feasts stay in their seasons.
Is there a heavenly calendar in the Bible?
Yes. Genesis 1:14 says God made the lights in the sky "for signs and seasons, and for days and years." The word for seasons is mo'adim, meaning appointed times. Psalm 104:19 says He "appointed the moon for seasons." The sun and moon set the dates of His feasts.