What is the structure of the Jewish calendar?

TL;DR:

The Jewish calendar is a lunisolar system that syncs the day, month, and year by tracking the Earth, moon, and sun. Its structure governs holidays, sabbaths, and sacred observances, showing God’s precise design in creation.

what does the bible say?

The Jewish calendar is a lunisolar calendar that coordinates three astronomical phenomena. The Earth rotates on its axis over the course of a day. The moon revolves around the Earth over the course of a month, every 29 ½ days. The Earth revolves around the sun over the course of a year, every 365 ¼ days or every 12.4 lunar months. The Jewish calendar includes all three.

The Jewish day begins at sundown and ends at sundown the following day, following the Genesis creation description, which punctuates specific creation events with “there was evening and there was morning” (Genesis 1:5, 8, 13, 19). Other references to the Jewish calendar are mainly concerning holidays. God instituted certain holidays to take place during specific months, for example, Passover during Nisan/Abib (Exodus 12:1-6, 14-17); Pentecost usually during Sivan (Leviticus 23:15-21); and Feast of Tabernacles during Tishrei (Leviticus 23:33-34). The New Testament also references these holidays, most notably when Jesus celebrated Passover before His crucifixion (Matthew 26:17-29; Mark 14:12-25; Luke 22:7-15) and the beginning of the early church at Pentecost (Acts 2:1). Regardless of what is celebrated when, the New Testament indicates that believers shouldn’t judge each other regarding such celebrations (Colossians 2:16).

from the old testament

Genesis 1 indicates that the Earth began in darkness and God first had to create light. Genesis 1:5 says, "God called the light Day, and the darkness he called Night. And there was evening and there was morning, the first day." Each successive day continues to be recorded in the same order "there was evening and there was morning." So the Jewish day begins at sundown and ends at sundown the following day.
The first day of the Jewish week is Sunday and the seventh day, known as Shabbat, is on Saturday. God instituted the Sabbath as part of Mosaic Law, included in the Ten Commandments (Exodus 20:8). The Israelites were forbidden to do any work on the Sabbath. In the Jewish calendar, to prevent certain holidays from interfering with Shabbat, an extra day is added to one month (Cheshvan) or subtracted from another (Kislev) the previous year.
These same adjustments are made for Yom Kippur, the Day of Atonement, God established after freeing the Israelites from Egypt (Leviticus 16). Because of Sabbath restrictions on certain activities, Yom Kippur should not fall next to Shabbat.

from the new testament

The Jewish calendar begins with the month of Nissan (in the spring when Passover is celebrated). Jesus’ last supper with His disciples was a Passover meal (Matthew 26:17-29; Mark 14:12-25; Luke 22:7-15) and His three-year ministry is often timed by the Passover celebration (John 2:13, John 6:4, John 13:1).
Certain events of the New Testament are mentioned in reference to holidays to give an idea of the month, such as the Feast of Tabernacles (John 7:2) and Pentecost (Acts 2:1).

implications for today

From hourglasses to sundials to rooster crows, people have used different tools throughout the ages to measure and organize time. And those are simple compared to the astrological calculations that go into calendar creation, such as the Jewish calendar. In Old Testament times, God instituted certain observances to fall during specific months. Today, Jews still use the Jewish calendar for those celebrations even though most use the Gregorian calendar in daily life.

The calendars we create are only possible because of the world God created. The regularity of natural processes, such as the Earth’s rotation around the sun, make it possible to organize time by days, months, and years. Considering that makes us marvel anew at our Creator. Our Lord is “not a God of confusion” (1 Corinthians 14:33), and He has created nature so precisely that we can rely on it to organize time. How can anyone not believe in a Creator when thinking about that precision?

Romans 1:19-20 implies that everyone actually does know: “For what can be known about God is plain to them, because God has shown it to them For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse.” It isn’t lack of knowledge that prevents people from embracing God; it is hardness of heart (John 3:19).

This is why Christians today must point others to Christ while there is still timeand pray that God softens hearts to hear His message of hope.

understand

The Jewish calendar is lunisolar, syncing days, months, and years with the sun and moon.
Days in the Jewish calendar begin at sundown, guiding Sabbaths and holidays.
Biblical events, like Passover and Pentecost, follow the Jewish calendar.

reflect

How does the Jewish calendar deepen your appreciation for God’s order in creation?
How can you apply the principle of marking time, like Sabbaths or holidays, to honor God in your own life?
How might you marvel at God’s faithfulness and reliability when you reflect on the regularity of days, months, and years?

engage

How does the Jewish lunisolar calendar reveal God’s intentional design in both nature and worship practices?
What insights can we gain from the timing of biblical events, like Passover and Pentecost, when we study the Jewish calendar?
How can understanding God’s order in time help us better coordinate our spiritual rhythms and observances today?