What was Paul’s purpose for using the OT in his letter to the Romans?

Paul was, of course, a Jew. What he and the other apostles wished to make clear was that Jesus was the promised Jewish Messiah, the One whose coming was foretold in the Old Testament. The unbelieving Jews rejected our Lord’s claim to be the Messiah, and they sought to “divorce” Christianity as non-Jewish, and therefore an illegal sect. In this they failed (Acts 18:12-17).

The whole Book of Romans deals with the relationship between the Old Testament and the New, the Jews and the Gentiles. Thus, Paul concludes in chapter 3 that all men, without exception (Jew and Gentile) are sinners, deserving of death, and in need of justification by faith. His final summation of man’s universal sinfulness is in Romans 3:10-18, where Paul draws together a number of Old Testament texts indicating man’s sin. Specifically, Paul wants to demonstrate the sin of the Jews, since they did not need to be persuaded that the Gentiles were sinners (see Galatians 2:15). He wants to show that even the “founding fathers” of Judaism were saved by faith, not by works—and so we find Romans 4 devoted to Abraham and his justification by faith. In Romans 9-11 Paul shows how God purposed from eternity past to save both Jews and Gentiles, and how the Jews’ rejection of Jesus opened the door to the evangelization of the Gentiles.

We know that Paul was privileged to explain and proclaim certain mysteries (see Romans 11:25; 16:25; Ephesians 1:9; Colossians 1, etc.). In particular, he was privileged to explain the mystery of the bringing together of Jews and Gentiles in “one body,” the church, through Christ (Ephesians 3:1ff.). A “mystery” in Paul’s usage is not something unrevealed, not ever mentioned earlier in the Bible. It is, rather, something that was indicated, but not understood as such. And so it is in Romans 9-11 that Paul draws together many Old Testament citations to show that God chose some and not others, and that some of these “others” were intended to be Gentiles. It was necessary to use a great deal of the Old Testament in the New to show the direct link between the two testaments, and to show that the work of Christ fulfilled the promises of God in the Old Testament.

Paul was, of course, a Jew. What he and the other apostles wished to make clear was that Jesus was the promised Jewish Messiah, the One whose coming was foretold in the Old Testament. The unbelieving Jews rejected our Lord’s claim to be the Messiah, and they sought to “divorce” Christianity as non-Jewish, and therefore an illegal sect. In this they failed (Acts 18:12-17).

The whole Book of Romans deals with the relationship between the Old Testament and the New, the Jews and the Gentiles. Thus, Paul concludes in chapter 3 that all men, without exception (Jew and Gentile) are sinners, deserving of death, and in need of justification by faith. His final summation of man’s universal sinfulness is in Romans 3:10-18, where Paul draws together a number of Old Testament texts indicating man’s sin. Specifically, Paul wants to demonstrate the sin of the Jews, since they did not need to be persuaded that the Gentiles were sinners (see Galatians 2:15). He wants to show that even the “founding fathers” of Judaism were saved by faith, not by works—and so we find Romans 4 devoted to Abraham and his justification by faith. In Romans 9-11 Paul shows how God purposed from eternity past to save both Jews and Gentiles, and how the Jews’ rejection of Jesus opened the door to the evangelization of the Gentiles.

We know that Paul was privileged to explain and proclaim certain mysteries (see Romans 11:25; 16:25; Ephesians 1:9; Colossians 1, etc.). In particular, he was privileged to explain the mystery of the bringing together of Jews and Gentiles in “one body,” the church, through Christ (Ephesians 3:1ff.). A “mystery” in Paul’s usage is not something unrevealed, not ever mentioned earlier in the Bible. It is, rather, something that was indicated, but not understood as such. And so it is in Romans 9-11 that Paul draws together many Old Testament citations to show that God chose some and not others, and that some of these “others” were intended to be Gentiles. It was necessary to use a great deal of the Old Testament in the New to show the direct link between the two testaments, and to show that the work of Christ fulfilled the promises of God in the Old Testament.