The Old And New Testaments Are Not Books
The Old Testament (covenant) is understood by most to be a collection of 39 books starting with Genesis and ending with Malachi.
The New Testament is understood to be a collection of 27 books starting with Matthew and ending with Revelation.
However, this is an incorrect understanding.
The Old and New Testaments (Covenant) are not a collection of books.
Instead, each testament reveals how God relates to people at different times in history.
OT = Old Testament
NT = New Testament
NOTE: some translations use the word covenant and others use the word testament. Either way, it is the same Greek word in the original manuscripts. There are not 2 covenants and 2 testaments for a total of 4 (OT, OC, NT, NC). There are only the OT or OC and NT or NC for a total of 2. The words covenant and testament as used in the Bible are interchangeable but not different.
The OT (covenant) communicated how God related to Israel under the Law of Moses (Book of the Law, Book of Moses, or Written Code) and is contained in Exodus 19-Leviticus and Deuteronomy.
The OT is based upon the Law of Moses.
The OT was in effect from Exodus 24 until Jesus died on the cross to establish the NT.
This means that the OT was not in effect during the Book of Genesis and for most of Exodus.
The NT is based upon the blood and cross of Jesus (Matthew 26:8; Luke 20:22).
It is a testament or covenant of grace (Hebrews 2:9), where he died for all of our sins.
The NT (covenant) communicates how God relates to everyone who receives his grace through faith in Jesus.
The OT (covenant) was a conditional (if, then) testament where blessings where based upon Israel's obedience to the law - which the Jewish people NEVER obeyed (Ten Commandments and all the other laws).
Under the OT, forgiveness for breaking the law was temporarily given through the animal sacrificial system (Leviticus).
The OT law, which included the Ten Commandments, was a testament of condemnation and death, was temporal, and had no glory compared to the new covenant of grace (Romans 7:14-25; 2 Corinthians 3:4-11).
Contained in the Jewish Scriptures was God's promise to replace the OT of Law with the NT (covenant) of Grace (Jeremiah 31:31-34).
In AD 33, the blood of Jesus established the NT (Hebrews 2:9), thus fulfilling Jeremiah 31:31-34 (Hebrews 8).
The NT replaced the OT (see Hebrews), which was established around 1500 BC by the blood of animals (Exodus 24).
In the NT, God remembers our sins no more because Jesus died for all of our sins (Hebrews 8:12, 10:17-18).
In the NT, God doesn't count our sins against us because all of our sins were counted against Jesus (2 Corinthians 5:19).
In the NT, forgiveness is complete and eternal (Hebrews 8-10).
In the NT, we have eternal life and are declared righteous (innocent, not guilty of breaking the 10 Commandments) by God (Romans 3:21-24; 2 Corinthians 3:9, 5:21).
In the OT, God promised to send his Spirt into the hearts of people so they could live and love (Deuteronomy 30:6).
In the NT, God redeems (sets free) people from the law through Jesus and sends the Spirit of Jesus into our hearts where we call God “Abba, Father” and where the Spirit produces love in and through us (Romans 5:5, 7:6, 8:15-17; Galatians 4:4-6, 5:23-23).
In the OT, God is a judge under law, even though all he ever wanted to be was Father (Jeremiah 3:19).
The New Testament (Covenant) of Grace replaced the Old Covenant (Testament) of Law (Hebrews 7:22, and Hebrews 8, 10).
The Old Testament went into effect with the blood of an animal (Hebrews 9:18-22; Exodus 24:6-8) and was in effect until Jesus died on the cross.
This makes Matthew and Luke books that contain mostly the OT for the people of Israel.
Just before his death, while in the upper room, Jesus told his disciples that through his blood, the NT would be established (Matthew 26:28; Luke 20:22).
He was not talking about books of the Bible when he said this.
Rather, he was talking about the new way people would relate to God, by grace through faith in Jesus and not by the Law of Moses.
The New Testament went into effect with the blood of Jesus (Matthew 26:28; Luke 22:20; Hebrews 9:24-10;18).
The New Testament is everything Jesus did for us to reconcile us to God (2 Corinthians 5:19-21).
We learn about this in Paul's letters such as Romans, Galatians, Ephesians, 2 Corinthians 3:1-6:2, Philippians, Hebrews, and Colossians.
If you are in Christ, you are a new creation.
The old covenant of law is gone and the new covenant of grace has come (2 Corinthians 5:17).
You are free now...you do not live under the condemnation of the law but live under the freedom of grace by the Spirit of Jesus who lives in you (2 Corinthians 3:18).