Themes are the fundamental and often universal ideas explored in a literary work.
Each of the books of the New Testament has a unique relationship to the Old Testament and to Judaism as a whole, ranging from the very Jewish Gospel of Matthew to the Gospel of Luke, which makes little or no reference to the Jewish scriptures. This range is largely due to the location and audience of the different authors of the New Testament. Matthew’s Gospel was written for a largely Jewish group to convince them that Jesus was the hoped-for Messiah, and so he interprets Jesus as someone who relives the experience of Israel. For Matthew, everything about Jesus is prophesied in the Old Testament. The Old Testament narratives to which Matthew refers served as ways in which early followers of Jesus could make sense out of his birth, death, and resurrection. In contrast, Luke makes little or no reference to the Hebrew scriptures because they would have been unfamiliar to his largely Gentile audience.
Paul introduces yet another perspective on the Hebrew Scriptures with his theology of “faith versus works,” which states that through Christ we are saved “through grace alone,” not through doing good works. Paul contrasts Christianity’s emphasis on the grace of God and the faith of the believer with the Jewish insistence on the law as the necessary means for salvation. Paul’s theology inaugurates a strong anti-Jewish tradition in Christianity, which claims that Christianity is a higher, more spiritual tradition than Judaism. This claim is called Christian supercessionism because it is based on the idea that the New Testament supercedes the Old Testament. Supercessionists believe that the laws laid down in the Old Testament are external, in the sense that they regulate human behaviors rather than spiritual states, and that these laws become unnecessary through Christ. Supercessionism simplifies the rich and subtle theology of the Old Testament, which makes no such distinction between faith and works.
Some scholars have argued that the New Testament’s references to sinners actually referred to those who were marginalized, poor, cast out, orphaned, diseased, or widowed. Jesus not only promises salvation to such sinners, but goes so far as to call their poverty itself “blessed” throughout the Gospels. At many points in Jesus’s ministry, he shocks mainstream Jews by associating with, ministering to, and healing people who are cast out, poor, and sick. Some have argued that a prominent theme in the Gospels is Jesus’s good news to such people and an invitation to the rich to join them.
In his final letter to the new churches in Romans, Paul summarizes his lifelong question about the relationship between Jewish law, which requires certain observances and actions, and faith in the grace offered by God through Jesus Christ, which is given freely and without regard for good works. This issue was particularly problematic in Rome because the early church consisted both of Jewish followers of Christ, who observed the law, and Gentile followers, to whom the law was relatively unknown. Paul concludes that the law is a gift from God, and can help people become more faithful, but ultimately we are justified by faith alone, and the grace of God is available to both Jews and Gentiles. In the end, Paul declares that only minimal observance of Jewish law is necessary to be a follower of Jesus—who himself, interestingly enough, was a law-abiding Jew.