The Old Testament and New Testament are unified in God’s overall revelation to us. However, there are specific, intended differences between the two. They are
distinctly separated by the life, death and resurrection of the Lord Jesus Christ.
And although God’s wrath on sinful humanity is much more prevalent in the Old Testament, while His grace toward the humble is much more prevalent in the New Testament, both the Old and New point to the Messiah, Jesus of Nazareth.
The Lord Jesus is in the Old Testament in picture (i.e. King David), prophecy (i.e. Isaiah 53:5) type (the scarlet cord Joshua 2:21 … click here for a list of many of the prophecies The Lord Jesus fulfilled) and appearance (Exodus 3:2), which are scattered throughout the entire Old Testament.
The Old Testament is the foundation, while the New Testament is the completion (Luke 4:21). The Old Testament contains different categories of books, including history, law, poetry/wisdom and prophecy, showing God’s judgement on sin (sprinkled with grace). While the New Testament shows God’s mercy and grace (sprinkled with judgement) focusing on the substitutionary death of the Lord Jesus Christ for sinners.
All combine to provide believers everything necessary to know the things of God that He desires we know. At the highest level, the most important of those things are:
1. God is Holy (Psalm 99:9). He is perfect in every way. That perfection includes love and mercy, but it equally includes righteousness.
2. All of mankind sins. We all choose to sin (Romans 3:10-14). We all do things that we know are wrong because God put that conscience in us when He created us.
3. The punishment for sin is eternal death, away from God in Hell (Romans 6:23). This is due to God’s perfect holiness. Just as a good civil judge on earth would not be right in allowing a criminal to go free, our Perfect God cannot let a sinner into His presence. That’s why the Father turned from (forsook) the the Lord Jesus before He said “My God, my God, why have you forsaken me” when he “became sin” on that cross. Sin MUST be punished.
4. Jesus Christ took the punishment for us. Because of the love and mercy that are a part of God, He came to earth and became flesh in the person of Jesus Christ. He lived a perfect, sinless life and then gave himself as a perfect sacrifice in our place!
Due to the death of Christ as our substitute, for all who repent of their sin and trust in the finished work that Jesus Christ completed at Calvary, God can legally dismiss our case, so to speak. This is because the Lord Jesus Christ died for us, as our substitute.
Think of a judge here on earth who’s son stands before him after having been caught committing a crime. Then the judge stands up, removes his robes, moves his son out of the way, and receives the righteous punishment that his son deserved. This is very similar to what the Lord Jesus did for believers.
Without the New Testament God’s Word to man would not be complete. And without the Old Testament the New Testament would not make much sense. When the Old and the New are combined, the product is the divine, inerrant Word of God!
It all fits together perfectly! When a person read’s God Word with an open mind and heart, he quickly finds that the Bible is a supernatural book that could not have been written by man. There are countless parallels between the old and the new and an unending well of living water within that continuously quenches the thirst of those who come to it as humble sinners in need of Him.
The Law of the Old Testament shows God’s Holiness and judgement on sin. While the New Testament shows God’s grace and love toward mankind. And it all points to the Lord Jesus Christ, who is the Way the Truth and the Life. No man comes to the Father, but by Him (John 14:6).