Why Keep the Old Testament in Our Bibles?

If Christians live under the New Covenant, why is more than half of our Bible the Old Testament?

Previous posts have established that the Law of Moses served a specific purpose, that God's plan was always moving toward Christ, and that we now live under the New Covenant. So why continue studying Abraham, Moses, David, Israel, the sacrifices, the temple, and the prophets?

The answer comes from an important distinction:

We are no longer under the Old Covenant, but that doesn't mean the Old Testament no longer has value.

The Old Testament is not our covenant, but it remains God's Word written for our learning.

Are Christians Picking and Choosing?

One common criticism of Christianity goes something like this:

"Christians pick and choose which parts of the Bible they want to follow. Leviticus condemns certain behaviors but also contains dietary restrictions. Why follow one and ignore the other?"

Similar arguments can be made about Israel's civil laws and penalties. If Christians really believe the Bible, why don't we enforce those laws today?

That argument sounds powerful if we treat the Bible as one enormous list of commands addressed equally to every person throughout history.

But it isn't.

The Law of Moses was a covenant given to Israel.

Christians don't disregard Mosaic dietary laws because we've arbitrarily decided we don't like them. We don't ignore Israel's civil laws because we're embarrassed by them. We aren't Israelites living under the Mosaic Covenant.

So when reading a biblical command, the question isn't simply, “Is this somewhere in the Bible?” We also need to ask, “Who was this given to, under what covenant, and does the New Testament establish it as God's will for Christians?”

That isn't picking and choosing Scripture.

It's understanding Scripture.

So What Do We Do With the Old Testament?

Paul answers that question directly:

“For whatever things were written before were written for our learning...” — Romans 15:4

The Old Testament wasn't preserved so Christians could continue living under the Mosaic Covenant.

It was preserved because we need what it teaches us. Here are 4 things we learn from the Old Testament.

#1 - We Learn Who God Is

There's a difference between knowing that someone exists and actually knowing them.

The same is true of God.

Believing there is a Creator is only the beginning. Scripture reveals what that Creator is actually like, beginning with the first words of the Bible:

“In the beginning God created the heavens and the earth.” — Genesis 1:1

Even that single verse tells us something about Him. God existed before creation. He possesses the power and intelligence necessary to create. Everything around us ultimately exists because of Him.

The rest of the Old Testament gives us thousands of years of interactions between God and humanity. We don't merely read that God is patient—we watch His patience with Israel. We don't merely hear that He is just—we see His response to sin. We see His mercy toward the repentant, His faithfulness to Abraham, His holiness in worship, and His love for His people.

If you want to know who God is, watch what He does.

#2 - We Learn God's Pattern

The covenant may change, but God's character doesn't.

The God revealed in the Old Testament is the same God we encounter in the New Testament. Throughout biblical history, we repeatedly see recognizable patterns in how He interacts with humanity.

God loves His creation. He expects those who trust Him to obey what He reveals. He teaches humanity about the seriousness of sin and the necessity of sacrifice. And He repeatedly demonstrates His desire to save.

God saved Noah from the Flood. He delivered Israel from Egypt and brought them through the Red Sea. He rescued His people from enemies and preserved the faithful through judgment.

Those acts of salvation prepare us to understand the ultimate salvation He provides through Christ.

God's methods of dealing with people under different covenants may change, but His character does not.

#3 - We Learn From Great Faith—and Terrible Failure

Hebrews 11 does something fascinating. A New Testament writer teaches Christians about faith primarily by pointing backward to people in the Old Testament.

Abel offered. Noah built. Abraham went. Sarah believed. Moses chose. Israel crossed. Rahab acted.

Then the writer essentially says there isn't enough time to keep listing examples and mentions Gideon, Barak, Samson, Jephthah, David, Samuel, and the prophets.

Why teach New Testament Christians using people who lived under previous covenants?

Because the specific commands may change, but the nature of faith remains recognizable:

Hear God → Trust God → Obey God.

But the Old Testament doesn't only give us examples to imitate. It also gives us mistakes to avoid.

Paul specifically points Christians toward Israel's failures in 1 Corinthians 10. Their idolatry, immorality, dissatisfaction, testing of God, and complaining became warnings for Christians who came centuries later.

That's one of the great values of biblical history.

We can learn from thousands of years of other people's faithfulness—and their failures—without having to repeat their mistakes ourselves.

#4 - We Learn the “Why” Behind the New Testament

Perhaps most importantly, the Old Testament helps us understand why the New Testament means what it means.

Hebrews describes the Law as:

“...a shadow of the good things to come...” — Hebrews 10:1

A shadow isn't the thing itself, but it tells you something is there. It gives you its shape and helps you recognize what's coming.

That's what so much of the Old Testament does for Christ.

• Why is Jesus called the Lamb of God?

• Why does His blood matter?

• Why do we need atonement?

• Why is Jesus our High Priest?

• Why was the temple veil being torn significant?

• Why does Hebrews talk about a Most Holy Place?

• Why do we even need a covenant?

The New Testament answers these questions, but the Old Testament gives us the framework necessary to fully appreciate those answers.

We Don't Live Under It, But We Need It

Christians don't need to choose between two extremes.

We shouldn't place ourselves back under the Law of Moses as though Christ never established a New Covenant. But neither should we treat the Old Testament as an outdated portion of Scripture that has little relevance to Christians.

Paul tells us exactly why it remains:

It was written for our learning.

Through it, we learn who God is. We see the consistency of His character. We encounter extraordinary examples of faith and sobering examples of failure. And perhaps most importantly, we gain the background necessary to understand what Jesus accomplished.

We don't live under the Old Testament, but we cannot fully understand the New Testament without it.