The Old Testament is foundational to Christianity because it tells the story and makes the promises that the New Testament presents as fulfilled in Jesus Christ. It reveals God’s character, records his covenant with Israel, and Jesus and the apostles treated it as Scripture.
Foundational Christian Scripture
The Old Testament is important to Christianity in part because it makes up roughly three-quarters of the Christian Bible and lays the groundwork for the New Testament. Christian reading of the New Testament assumes the story already being told: who God is, how he relates to his people, and the covenant context in which later claims about Jesus are presented.
In this sense, the Old Testament is not an optional preface but a foundational portion of the Bible that sets up the themes and expectations that appear again in the New Testament.
Jesus and the apostles
Another reason the Old Testament matters is that Jesus and the apostles quoted it constantly and treated it as the authoritative word of God. This means the earliest Christian teaching did not present the Old Testament as a discarded or irrelevant collection; it functioned as Scripture within the life and message of the church.
Because Jesus and the apostles treated these writings as authoritative, Christianity historically has received the Old Testament as part of its Bible and as essential background for understanding the message of the New Testament.
Promises and fulfillment
The Old Testament contains promises, prophecies, and pictures that the New Testament presents as fulfilled in Christ. This includes a broad pattern of expectation and anticipation: from the sacrifices to the promised Messiah. The New Testament’s claim is not merely that Jesus appeared with a new message, but that his life and mission complete what the earlier Scriptures were pointing toward.
That is why Christian reading often connects the Old Testament’s themes and images with Jesus: the New Testament frames Jesus as the fulfillment of what the Old Testament was promising and portraying.
Key verse
“Then he said to them, ‘These are my words that I spoke to you while I was still with you, that everything written about me in the Law of Moses and the Prophets and the Psalms must be fulfilled.’” (Luke 24:44)
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This verse is significant for the question because it explicitly presents Jesus as teaching that the Scriptures “concerning me” must be fulfilled. It captures the Christian conviction that the Old Testament is not simply a record of ancient religion, but part of the scriptural witness that points forward to Christ and is completed in him.
Frequently Asked Questions
Why do Christians read the Old Testament at all?
Christians read the Old Testament because it is foundational to Christianity: it makes the promises and tells the story that the New Testament presents as fulfilled in Jesus Christ. It also lays the groundwork for understanding the New Testament’s message.
Is the Old Testament considered Scripture in Christianity?
Yes. A key reason is that Jesus and the apostles quoted it constantly and treated it as the authoritative word of God. That practice shows that the Old Testament functioned as Scripture within early Christian teaching.
How does the Old Testament relate to Jesus?
The New Testament presents the Old Testament’s promises, prophecies, and pictures—ranging from the sacrifices to the promised Messiah—as fulfilled in Christ. Luke 24:44 summarizes this by recording Jesus’ teaching that what was written “about me” in the Scriptures “must be fulfilled.”
Does the Old Testament still matter if the New Testament exists?
According to the way Christianity understands its Bible, the Old Testament still matters because it makes up roughly three-quarters of the Christian Bible and lays the groundwork for the New Testament. The New Testament’s presentation of Jesus as fulfillment depends on what the Old Testament promised and portrayed.
What is a simple way to summarize the Old Testament’s importance?
It is important because it reveals God’s character, records his covenant with Israel, and provides the promises and scriptural framework that the New Testament presents as fulfilled in Jesus Christ—an approach reflected in Jesus’ words in Luke 24:44.