Christians need to understand the relationship between the beliefs and practices of the Old and New Testaments because it helps them to understand the continuity and development of God's plan of salvation. The Old Testament lays the foundation for the coming of Jesus Christ, and the New Testament reveals the fulfillment of the prophecies and promises of the Old Testament. The Old Testament laws and practices were given to the Israelites to reveal God's character and prepare them for the coming of the Messiah, but they were not meant to be permanent. The New Testament teaches that salvation is through faith in Jesus Christ, not obedience to the Old Testament laws. Understanding this relationship helps Christians to see the unity of God's plan and the significance of Jesus Christ as the fulfillment of Old Testament prophecy and the embodiment of God's love and grace.
One of the areas of Christian beliefs and practices that some Christians and non-Christians find confusing is how to reconcile the Old Testament Laws and practices with Christian beliefs and practices. St. Augustine adeptly described the relationship between the Old and New Testaments as follows: "The new is in the old concealed; the old is in the new revealed." In other words, the two work together. One has to read both the Old and New Testaments simultaneously to follow the plot of the salvation story. I have often said that one cannot understand the book of Hebrews in the New Testament without understanding the Old Testament.
Augustine's statement highlights the idea that the Old and New Testaments are interconnected and that the New Testament fulfills the promises and prophecies found in the Old Testament. The New Testament is a revelation of the mysteries hidden in the Old Testament, and the Old Testament provides the historical and theological foundation for the New Testament.
To make a robust theological argument for this statement, one could begin by looking at the themes and motifs that run through the Old and New Testaments. For example, the theme of redemption is central to both the Old and New Testaments, and the New Testament reveals the ultimate fulfillment of this theme in the person and work of Jesus Christ.
In the Old Testament, we see God's plan of salvation unfolding through the history of Israel, with promises and prophecies pointing forward to the coming of a Messiah who would bring salvation to God's people. The Old Testament sacrificial system also foreshadowed the ultimate sacrifice of Jesus on the cross.
The New Testament reveals how Jesus fulfills these promises and prophecies and how his death and resurrection provide the ultimate redemption for God's people. The New Testament also sheds light on the nature of God and the relationship between God and humanity, revealing how the God of the Old Testament is the same revealed in the person of Jesus Christ.
Moreover, the New Testament provides a lens through which we can better understand the Old Testament. The apostles and writers of the New Testament often use Old Testament texts and stories to explain and interpret the significance of Jesus and his teachings. For example, the book of Hebrews shows how Jesus is the ultimate fulfillment of the Old Testament sacrificial system and how his sacrifice provides a way for us to approach God.
The Book of Hebrews is a powerful testament to the idea that the New Testament fulfills the signs and symbols of the Old Testament. Throughout the book, the author draws on various Old Testament passages and symbols to demonstrate how they find their ultimate fulfillment in the person and work of Jesus Christ.
One of the main ways that the Book of Hebrews demonstrates the fulfillment of the Old Testament signs and symbols is through the concept of "types and shadows." The author argues that the Old Testament contains various types and shadows of things to come in the future and that these things find their ultimate fulfillment in Jesus Christ.
For example, the author of Hebrews uses the image of the high priest in the Old Testament to demonstrate how Jesus serves as the ultimate high priest who makes a perfect sacrifice for the people's sins. The author also uses the imagery of the tabernacle and the sacrificial system to show how Jesus fulfills these symbols by providing a way for people to come to God through his sacrifice on the cross.
Furthermore, the author of Hebrews emphasizes that the Old Testament law and covenant were only temporary measures that pointed to the ultimate fulfillment in Jesus Christ. He argues that the Old Testament sacrifices and rituals were only shadows of the reality to come and that Jesus is the true and ultimate reality that those things pointed.
Thus, the Book of Hebrews demonstrates how the New Testament fulfills the signs and symbols of the Old Testament by showing how Jesus Christ is the ultimate fulfillment of those signs and symbols. It emphasizes how Jesus Christ brings an end to the temporary measures of the Old Testament and inaugurates a new covenant that provides forgiveness of sins and a way for people to come to God. The Book of Hebrews helps to demonstrate the unity of the Bible and the coherence of Christian theology, as it shows how the Old and New Testaments are connected and how they work together to reveal the ultimate truth about God and his plan for humanity.
Therefore, Augustine's statement highlights the importance of seeing the Old and New Testaments as interconnected and mutually illuminating. The Old Testament provides the historical and theological foundation for the New Testament, and the New Testament reveals the ultimate fulfillment of the promises and prophecies found in the Old Testament. This understanding of the unity of the Scriptures is essential for a robust and coherent Christian theology.