These chapters are difficult and controversial!
The American Religious Right has bought into Zionism and so US foreign policy follows that. Many Christians, inspired by the Scofield Bible and US Television preachers, buy into a version of Christianity which I believe is wholly at odds with Paul’s writings here, and based on a misunderstanding of OT prophecy. They teach that there are different dispensations of history and that currently we are in the age of the church, which is a parenthesis in God’s plan which has always been about Israel. So they look for a rapture of the church and then the final dispensation would be about Israel with the temple rebuilt and sacrifices reinstated. Gentile believers would be in the new heaven and Jews on a new earth. Absolute nonsense and total heresy!
Jesus was the fulfilment of the temple and his sacrifice was the fulfilment of all sacrifices. The promise in Genesis 12:1-3, that “all the families of the earth will be blessed” by Abraham’s offspring, is fulfilled in the gospel, drawing Jews and Gentiles into one new man in Christ. The church is not a parenthesis in God’s plan, it is God’s plan. So in this passage Paul allegorises the people of God, now the church, as an olive tree – unbelieving Jews represent broken off branches and new branches are grafted on that represent believing Gentiles. The widespread salvation of Gentiles is provoking the Jews to jealousy. One day, Paul teaches, the full number of Gentiles will have been saved and then there will be a widespread revival among Jews – coming to Christ.
After the holocaust and then the founding of the secular state of Israel in 1948, Jews demanded Christian missionary efforts to stop. Many are squeamish about evangelism among Jews. So some developed a two covenant theology, the old Abrahamic covenant carrying on for Jews. No! The old covenant is obsolete! Paul envisages a steady trickle of Jews coming into the church saved by grace through faith and then a widespread end time revival among Jews.
Come on Lord, do it! Use us to see Gentiles and Jews saved. Amen!