Judaism is one of the world’s oldest monotheistic religious traditions, but calling it simply a “religion” doesn’t quite capture it. Judaism is also a people, a history, a culture, a body of literature, and a way of life. A person can be Jewish and deeply observant, Jewish and largely secular, or somewhere between the two. That makes Judaism a little different from religions in which identity is primarily defined by what a person believes.

For Christians, Judaism is also unlike any other non-Christian religion. Christianity didn’t develop independently and then discover Judaism later. Jesus was Jewish. His disciples were Jewish. The apostles were Jewish. The Hebrew Scriptures became the Christian Old Testament, and virtually every major Christian concept—from creation, covenant, and sin to sacrifice, Messiah, resurrection, and the kingdom of God—comes to us through the world of Israel.

Christianity and Judaism therefore share a remarkable amount of history and Scripture.

And yet they disagree about the person standing at the center of Christianity.

Jesus.

Abraham, Israel, and the Covenant

The biblical story of Judaism begins with Abraham, whom God called and promised to make into a great nation. That covenant continued through Abraham’s son Isaac and his grandson Jacob, whose name was changed to Israel.

Jacob’s descendants became the people of Israel.

According to the biblical account, God later delivered the Israelites from slavery in Egypt through Moses and entered into covenant with them at Mount Sinai. The Torah gave Israel commandments governing worship, morality, family life, justice, food, festivals, sacrifice, and many other aspects of life.

This helps explain something that Christians sometimes miss about Judaism. Biblical faith wasn’t merely a matter of believing certain things about God. Israel was called to live as a covenant people.

That concept remains fundamental to Jewish identity.

The Torah and the Hebrew Bible

The most important sacred text in Judaism is the Torah, meaning in its narrower sense the first five books of the Bible: Genesis, Exodus, Leviticus, Numbers, and Deuteronomy.

The larger Jewish Bible is commonly called the Tanakh. The name comes from its three major divisions:

Torah — Law or Instruction

Nevi’im — Prophets

Ketuvim — Writings

These books substantially correspond to what Christians call the Old Testament, although they’re arranged and categorized differently.

But knowing the Tanakh alone isn’t enough to understand modern Judaism.

That’s because Judaism continued developing through centuries of interpretation, debate, worship, and religious practice. The destruction of the Jerusalem Temple in A.D. 70 was especially significant. Without the Temple and its sacrificial system, Jewish religious life increasingly centered around Torah, prayer, synagogue life, and rabbinic interpretation.

The Judaism that developed from that world is usually called Rabbinic Judaism.

The Talmud and Rabbinic Tradition

Alongside the written Torah developed an extensive tradition concerning how the commandments should be understood and practiced.

The Mishnah, compiled around A.D. 200, preserved generations of rabbinic legal discussion and tradition. Later rabbinic discussions surrounding the Mishnah became the Gemara. Together, the Mishnah and Gemara form the Talmud.

And if you imagine the Talmud as a Jewish version of a systematic theology textbook, you’re probably going to be confused very quickly.

Rabbinic literature often preserves arguments rather than simply handing the reader a neat list of conclusions. Rabbis debate Scripture, law, hypothetical situations, customs, ethics, and the reasoning of earlier rabbis. Sometimes competing opinions remain right there on the page.

There’s something wonderfully Jewish about that.

The question isn’t always merely, “What is the answer?”

Sometimes it’s, “Why do you think that’s the answer?”

Jewish Law and Daily Life

Jewish religious law is known as halakha. It encompasses far more than what Christians usually mean when they speak about religious rules. It can concern prayer, food, marriage, business, holidays, clothing, Sabbath observance, family relationships, and countless details of ordinary life.

Different Jewish movements understand the authority of halakha differently.

For observant Orthodox Jews, keeping the commandments shapes the rhythm of everyday existence. Shabbat, the Sabbath, begins at sunset Friday and continues until nightfall Saturday. Dietary laws govern what foods are kosher and how they’re prepared. Jewish holidays repeatedly bring the community back to the defining events of Jewish history.

Passover remembers the Exodus.

Shavuot is associated with the giving of the Torah.

Rosh Hashanah marks the Jewish New Year.

Yom Kippur, the Day of Atonement, is a solemn day of repentance and fasting.

Sukkot recalls Israel’s wilderness experience.

Hanukkah commemorates the rededication of the Temple following the Maccabean revolt.

Not every Jewish person observes these practices in the same way—or observes them at all. In fact, Jewish identity can remain extremely important even among people who rarely attend synagogue. Pew’s study of American Jews found considerable participation in Jewish holidays, foods, traditions, and family customs even where conventional measures of religious observance were relatively low. Pew Research Center

The Major Branches of Judaism

Modern Judaism isn’t one uniform religious movement. The categories are particularly useful when discussing Judaism in North America; outside North America, Jewish identities don’t always fit neatly into the same denominational structure.

Orthodox Judaism maintains the traditional authority of Torah and halakha. Orthodoxy itself contains considerable diversity, ranging from Modern Orthodox communities that participate extensively in contemporary society to Haredi and Hasidic communities that maintain much greater separation from secular culture.

Conservative Judaism, also called Masorti Judaism in many places outside North America, attempts to preserve the authority and continuity of Jewish tradition while permitting historical development and adaptation.

Reform Judaism gives substantially greater latitude to individual judgment and understands Jewish tradition in a more progressive and adaptable way.

Reconstructionist Judaism emerged from the thought of Rabbi Mordecai Kaplan, who famously described Judaism as the evolving civilization of the Jewish people.

And then there are plenty of Jews who don’t identify with any branch at all.

In Pew’s 2020 survey of American Jews, 37% identified as Reform, 17% Conservative, 9% Orthodox, 4% with other branches, and 32% with no particular branch. Those are American figures, however, and shouldn’t be treated as a picture of Judaism worldwide.

What Do Jews Believe About God?

Here we need to be careful.

It’s tempting for Christians to construct a list titled “What Jews Believe” as though Judaism had a creed comparable to the Apostles’ Creed or a statement of faith on a church website.

It doesn’t work quite that neatly.

Historic Judaism is emphatically monotheistic. The Shema, taken from Deuteronomy 6:4, stands at the heart of Jewish confession:

“Hear, Israel: Yahweh is our God. Yahweh is one.”

God is the Creator, the God of Abraham, Isaac, and Jacob, and the God who entered into covenant with Israel.

But contemporary Jews differ considerably in how they understand God—or even whether they believe in God at all. Pew found striking differences among American Jewish movements: belief in the God described in the Bible was overwhelmingly common among Orthodox respondents but much less common among Conservative and Reform Jews. Pew Research Center

Once again, Judaism is more than a checklist of theological propositions.

It’s the religious and historical life of a people.

The Messiah

The Hebrew word Mashiach, or Messiah, means “anointed one.”

The Hebrew Scriptures developed expectations of God’s future restoration of Israel and of a ruler associated with the line of David. Jewish messianic expectations have taken different forms throughout history, and modern Jewish movements don’t all understand the Messiah in precisely the same way. Some anticipate a personal Messiah; others emphasize a future messianic age characterized by peace and justice.

This brings us to the great dividing line between Judaism and Christianity.

Christians believe the Messiah has already come.

Jews do not.

Jesus and Judaism

Jesus wasn’t an outsider criticizing a religion to which He didn’t belong.

He was born into a Jewish family. He was circumcised. He attended Jewish festivals. He quoted the Torah and the Prophets. He taught in synagogues. His earliest followers were Jews, and the controversies recorded in the Gospels often make the most sense when understood as disputes occurring within the Jewish world of the first century.

The earliest Christian proclamation was therefore not, “We have discovered a new religion.”

It was that the promises made to Israel had reached their fulfillment in Jesus of Nazareth.

Christians came to believe that Jesus is Israel’s Messiah, that He died and rose from the dead, and ultimately that He shares in the divine identity.

Rabbinic Judaism rejected those claims.

That disagreement eventually contributed to Christianity and Judaism developing into distinct religious traditions.

But their separation shouldn’t cause us to forget where Christianity came from.

When Christians read Abraham, Moses, David, Isaiah, Jeremiah, and the Psalms, we’re reading Israel’s Scriptures. When we call Jesus “Christ,” we’re using the Greek word Christos for the Hebrew concept of Messiah. When Christians speak about a “new covenant,” we’re using language drawn from the Jewish prophet Jeremiah.

You really can’t understand Christianity very well without understanding Judaism.

Judaism and Christianity

Judaism and Christianity agree about many foundational things. Both affirm the God of Abraham, Isaac, and Jacob. Both look to the Hebrew Scriptures. Both inherit the biblical stories of creation, the patriarchs, the Exodus, Israel, the kings, and the prophets. Both speak about covenant, righteousness, repentance, judgment, and redemption.

But once again, everything eventually comes back to Jesus.

Christians believe that the God of Israel has acted decisively through Him.

Judaism doesn’t accept that claim.

For Christians, Jesus is the promised Messiah and risen Lord. For Judaism, Jesus doesn’t fulfill the role Judaism expects of the Messiah, and Judaism doesn’t accept the Christian doctrines of His deity, incarnation, or resurrection as defining truths of Jewish faith.

That is an enormous disagreement.

But disagreement doesn’t erase the shared history that came before it.

Why Christians Should Understand Judaism

Christians have another reason for approaching Judaism carefully: our history hasn’t always been admirable.

Jewish communities have experienced centuries of persecution in societies that identified themselves as Christian. Anti-Jewish preaching, forced conversions, expulsions, violence, and other forms of antisemitism have left a historical legacy that shouldn’t be ignored when Christians and Jews talk about faith today.

Understanding Judaism therefore requires more than learning the difference between kosher and non-kosher food or memorizing the Jewish holidays.

It means learning to see Christianity in its original setting.

The Last Supper didn’t happen in a cultural vacuum. Paul didn’t invent words like covenant, righteousness, Messiah, and resurrection from scratch. The arguments of the New Testament emerged from a world already saturated with Israel’s Scriptures, traditions, hopes, and debates.

Christianity claims that Israel’s story leads to Jesus.

Judaism says that it doesn’t.

And there, once again, we arrive at the question that keeps appearing whenever Christianity encounters another faith:

Who is Jesus?

For Christians, there may be no better way to understand that question than by first understanding the people, Scriptures, and promises from which it came.