God’s Calendar: Understanding the Biblical and Jewish Reckoning of Time

The Age of the Earth and the Creation Account

Some may question the traditional Jewish year—5786, as of September 2025—arguing that science has established the earth to be approximately 4.5 billion years old. How, then, can one believe the biblical account that God created the world in six days?

Consider this: according to Jewish tradition, Adam was created as a fully mature man, likely around 30 years old. If Adam had been created as an infant, he would not have been able to tend the Garden, name the animals, or fulfil his God-given role. Therefore, God created him with age built-in, fully formed and capable from the first moment.

In the same way, it is entirely within God’s power to create the earth with built-in age. God, as the ultimate Creator, could embed layers of history, fossils, and geological formations into the earth—not to deceive, but to give the earth character, beauty, and functionality.

Think of a skilled artist. He begins with a blank canvas, then applies layers upon layers of paint. He might scratch or scrape the surface, apply texture, even use unconventional tools to bring depth and character to the work. Though completed in just a few days, the final painting might look ancient—rich with story and complexity. To the untrained eye, it could appear to be a priceless relic from a distant past. Its value does not come from how long it took to make, but from the mastery and intention behind its creation.

Likewise, God could have formed the world in six literal days and infused it with fossils, geology, and features that suggest age—not to deceive, but to give the earth character, function, and beauty. Creation was not only efficient, it was priceless—crafted by the greatest Artist of all.

The Jewish Calendar: A Lunisolar System

The Jewish calendar is lunisolar—it synchronises both the moon’s phases and the solar year. Months begin with the new moon, while the solar year ensures that festivals like Passover remain in their correct agricultural season (Deuteronomy 16:1).

The command to track the new moon was the first national commandment given to Israel after the Exodus:

“This month shall be unto you the beginning of months” (Exodus 12:2).

How Months Were Determined: 29/30-Day Lunar Months and the Role of the Sanhedrin

In the ancient Jewish calendar, months were based on the moon’s cycle (approximately 29.5 days). Since a month cannot have half-days, months were either:

• 29 days (called a “defective” month), or
• 30 days (called a “full” month).

Here’s how it worked:

✅ Witnesses would report the sighting of the first sliver of the new moon to the Sanhedrin in Jerusalem.
✅ If the moon was sighted on the 30th day, that day was declared Rosh Chodesh (the New Month).
✅ If no moon was seen due to clouds, weather, or other factors, the 30th day automatically became Rosh Chodesh by default.

This system is described in the Mishnah (Rosh Hashanah 2:7–9):

If the witnesses did not arrive by the 30th day, the court would complete the month at 30 days, and the new month would begin the following day.

🔎 This sometimes led to two consecutive special days:

• The 30th day (the final day of the old month), and
• The 1st day of the new month.

These were not Sabbaths, but festive days (especially for Rosh Chodesh or Rosh Hashanah).

Did the New Moon Affect the Weekly Sabbath?

✅ No.
The weekly Sabbath (Shabbat) was always observed every seventh day, following a continuous, uninterrupted cycle from Creation (Genesis 2:2–3, Exodus 20:8–11).
It did not depend on moon sightings or the length of the lunar month.

For example:

• If the new moon wasn’t sighted, the Sanhedrin might delay declaring the new month, but the Sabbath continued on its regular 7-day rhythm.
• The idea of a “second Sabbath” or a lunar-based Sabbath is a modern theory with no support in the Torah, Talmud, or Jewish history.

From Observational to Fixed Calendar

This observational system—based on moon sightings and Sanhedrin rulings—was used from biblical times until the 4th century CE.

In 358 CE, during a time of severe Roman persecution, Hillel II, head of the Sanhedrin, introduced a fixed calendarbased on mathematical calculations and the 19-year Metonic cycle. This shift was necessary because:

• The Sanhedrin could no longer operate safely in the Roman Empire.
• The diaspora needed a standardised calendar to observe festivals at the correct times.

Important clarification:
✅ The fixed calendar did not replace the lunar system with a solar one like the Julian calendar.
✅ It preserved the lunisolar structure but removed the need for witnesses.
✅ Months still had 29 or 30 days, and the seven-day Sabbath cycle continued as always.

While the Julian calendar became the civil calendar of the Roman Empire, the Jewish religious calendar remained distinct. Jews never officially adopted the Julian calendar for religious observance.

The Myth of the Lunar Sabbath

Some groups today claim that the “true Sabbath” was originally tied to the lunar cycle, shifting each month depending on the new moon. According to this theory, the Sabbath might fall on a Tuesday one month, a Thursday the next, and so on.

However, this theory is not supported by:

✅ Biblical evidence: The Sabbath is the seventh day, established at Creation (Genesis 2:2–3) and commanded at Sinai (Exodus 20:8–11).
✅ Historical records: The Talmud, Mishnah, and Jewish tradition uniformly maintain a continuous 7-day week independent of the moon.
✅ Practical worship: The weekly Sabbath is a fixed cycle—not a floating feast tied to lunar observation.

While Rosh Chodesh (the New Month) could shift based on sightings, the Sabbath never moved.

Why Christians Are Not Obliged to Keep the Sabbath

While the Sabbath is a sign of the Mosaic covenant (Exodus 31:13,17), the New Testament teaches that believers in Jesus Christ are not under the Mosaic Law, including Sabbath observance. Instead, faith in Christ is the basis of righteousness, not adherence to specific days.

Key Scriptures include:

• Colossians 2:16–17:
  

  “Therefore let no one judge you in food or in drink, or regarding a festival or a new moon or sabbaths, which are a shadow of things to come, but the substance is of Christ.”

• Romans 14:5–6:
  

  “One person esteems one day above another; another esteems every day alike. Let each be fully convinced in his own mind.”

• Galatians 4:9–11:
  

  “But now… how is it that you turn again to the weak and beggarly elements… You observe days and months and seasons and years. I am afraid for you…”

The early church worshipped on Sunday, the day of Christ’s resurrection (Acts 20:7; Revelation 1:10). While the principle of rest and worship remains, the legal obligation to keep the Sabbath day as part of the Mosaic Law is not required for those in the New Covenant.

A 7,000-Year Timeline

Jewish tradition holds that human history spans 7,000 years, mirroring the seven days of creation. The Talmud (Sanhedrin 97a) divides history into:

1. 2,000 years of chaos (before Torah),
2. 2,000 years of Torah,
3. 2,000 years of the Messianic era.

The seventh millennium is viewed as a Sabbath rest—a time of universal peace under the Messiah.

Conclusion

The Jewish calendar is an intricate blend of divine instruction, astronomical insight, and rabbinic stewardship. While some modern views attempt to reconstruct or reinterpret Sabbath observance, both Scripture and tradition support a consistent weekly Sabbath tied to a seven-day cycle—not a shifting lunar model. For Christians, the Sabbath finds its ultimate fulfilment in Christ, who invites all to enter His rest (Hebrews 4:9–10).

The Seven Jewish Feasts: Origins, Meanings, and Christian Fulfilment

The Biblical Feasts of the Lord

In Leviticus 23, God gave the people of Israel a sacred calendar with seven appointed times (mo’edim)—feast days that reveal His plan for humanity. These feasts were divine appointments that not only shaped Israel’s life but also pointed forward to the work of the Messiah.

1️⃣ Passover (Pesach) – Freedom and Redemption

Origin: Exodus 12. Commemorates Israel’s deliverance from Egypt.

When: 14th of Nisan.

Meaning: Redemption through the blood of the lamb.

Christian Fulfilment: Jesus’ crucifixion as the Lamb of God (1 Corinthians 5:7).

2️⃣ Feast of Unleavened Bread (Chag HaMatzot) – Sanctification and Purity

Origin: Exodus 12:15–20. A week of eating unleavened bread, symbolising the removal of sin.

When: 15th–21st of Nisan.

Meaning: Call to holiness and removal of sin.

Christian Fulfilment: Jesus’ sinless body in the grave (John 6:35; Acts 2:31).

3️⃣ Feast of Firstfruits (Yom HaBikkurim) – New Life and Resurrection

Origin: Leviticus 23:9–14. Offering the first sheaf of barley.

When: The day after the Sabbath following Passover.

Meaning: Thanksgiving for new life and harvest.

Christian Fulfilment: Jesus’ resurrection as the firstfruits (1 Corinthians 15:20–23).

4️⃣ Feast of Weeks (Shavuot / Pentecost) – Empowerment and Harvest

Origin: Leviticus 23:15–21. A celebration of the wheat harvest and the giving of the Torah.

When: 50 days after Firstfruits.

Meaning: Harvest and thanksgiving; receiving the Law.

Christian Fulfilment: The outpouring of the Holy Spirit and the birth of the Church (Acts 2).

The Remaining Three Feasts: Future Prophetic Fulfilment

5️⃣ Feast of Trumpets (Yom Teruah / Rosh Hashanah) – Awakening and Gathering

Origin: Leviticus 23:23–25; Numbers 29:1–6. A day of blowing trumpets and spiritual awakening.

When: 1st of Tishrei.

Meaning: Call to repentance and readiness.

Future Fulfilment: The rapture or gathering of the saints (1 Thessalonians 4:16–17).

6️⃣ Day of Atonement (Yom Kippur) – Cleansing and Judgment

Origin: Leviticus 16; 23:26–32. The high priest makes atonement for the people.

When: 10th of Tishrei.

Meaning: National repentance and forgiveness.

Future Fulfilment: Israel’s national repentance and salvation (Zechariah 12:10; Romans 11:26).

7️⃣ Feast of Tabernacles (Sukkot) – Restoration and Joy

Origin: Leviticus 23:33–44. A celebration of God’s provision and presence in the wilderness.

When: 15th–21st of Tishrei.

Meaning: Joy, provision, and God’s dwelling with His people.

Future Fulfilment: The Millennial Kingdom and God’s eternal dwelling with humanity (Zechariah 14:16–19; Revelation 21:3).

Summary Table

Conclusion

The seven feasts of the Lord reveal God’s plan for redemption. The first four were fulfilled in Jesus’ first coming; the final three point to His return, Israel’s restoration, and the establishment of His Kingdom on earth.