True biblical doctrine is rarely confined to a single Testament, a single passage, or an isolated verse of Scripture. Sound doctrine is established by the whole counsel of God, with multiple witnesses throughout Scripture.
A strong biblical doctrine will normally have supporting testimony from both the Old and New Testaments, where such testimony is applicable. The Old Testament establishes patterns, principles, promises, and prophetic foundations, while the New Testament brings those truths into their fullest covenantal expression through Jesus Christ.
This does not mean that every Old Testament command is carried over unchanged into the New Covenant. The Bible must always be read according to its covenantal context and in the light of the finished work of Christ.
The governing center of biblical interpretation is therefore the Death, Burial, Resurrection, and Ascension of the Lord Jesus Christ. These events did not change the character of God. God did not become different after the Cross. Rather, Christ's finished work changed the covenantal way in which God's people approach Him, relate to Him, and live before Him.
The same God who spoke in the Old Testament is revealed fully in Jesus Christ:
“Jesus Christ is the same yesterday, today, and forever.”
— Hebrews 13:8 NKJV
The New Covenant does not give us a different God. It gives us a fuller revelation of God's redemptive purpose accomplished through His Son.
Jesus Himself taught His disciples to understand the Scriptures in light of Himself. After His resurrection, He explained that the Law of Moses, the Prophets, and the Psalms spoke concerning Him:
“These are the words which I spoke to you while I was still with you, that all things must be fulfilled which were written in the Law of Moses and the Prophets and the Psalms concerning Me.”
— Luke 24:44 NKJV
Therefore, we do not discard the Old Testament. Neither do we read the Old Testament as though Christ had never come. We read the Old Testament through the revelation of Christ and the New Covenant.
This gives us an important principle for establishing doctrine:
A biblical doctrine should be tested by multiple witnesses in Scripture, interpreted according to its context, and understood in the light of the finished work of Jesus Christ.
The Old Testament provides an important witness. The New Testament provides an important witness. Where both Testaments speak to a principle, their testimony carries particular weight. Where the New Covenant fulfills, transforms, or supersedes an Old Covenant practice, the New Testament must govern how that truth is applied to the Church.
This approach protects us from two opposite errors.
First, we must not build doctrine by isolating one verse while ignoring the rest of Scripture.
Second, we must not take an Old Testament practice and automatically impose it upon the New Covenant without asking how Christ's finished work affects its application.
The Bible is one unified revelation of God, but it unfolds progressively through God's dealings with humanity and reaches its center and fulfillment in Jesus Christ.
Therefore, when we establish doctrine, we should ask:
What does the Old Testament reveal about this subject?
What does the New Testament reveal about this subject?
How does Jesus Christ fulfill, clarify, or transform what was previously revealed?
What did His Death, Burial, Resurrection, and Ascension accomplish concerning this truth?
How does the New Covenant instruct believers to understand and practice it?
Are we building doctrine from the whole witness of Scripture or from an isolated passage?
The goal is not to make the Old Testament fight against the New Testament. The goal is to allow Scripture to interpret Scripture, while recognizing that the Lord Jesus Christ is the center of God's redemptive revelation.
“God, who at various times and in various ways spoke in time past to the fathers by the prophets, has in these last days spoken to us by His Son.”
— Hebrews 1:1–2 NKJV
The Multi-Testament Witness therefore becomes a foundational rule for this doctrinal work:
We will seek multiple biblical witnesses rather than isolated proof texts. We will consider both Testaments where applicable. We will honor the Old Testament as the inspired Word of God. We will interpret the Scriptures in the light of Jesus Christ and His finished work. And we will apply every doctrine according to the covenant in which God's people now live—the New Covenant established through the blood of Jesus Christ.