Jews and Gentiles Contrasted and Compared to an Olive Tree
Paul devotes what was eventually broken up into an entire chapter of Romans talking about the history of the Jews and the Gentiles as symbolized by an olive tree.
Olive trees were important to the people of the Mediterranean, and still are today to some extent. Most would have been familiar with their growth and care, at least in a rudimentary way. They would also be familiar with how orchards were extended and tended.
In Romans 11:1-5, Paul talks of his ancestry and reminds his readers of the times of Elijah. There, Elijah was crying out to God that he was the only prophet left and the only one who remained in Israel who was true to God and God had to remind Elijah that God had retained 7,000 other men who hadn't bowed down to worship Baal. Just as there was a remnant in Israel who were true to God then, so there were those true to God now. Paul was one.
In Romans 11:6-10 he reminds them of David speaking of the blindness of the people toward God. The works of the law were no more. Jesus had conquered works. Just as works were no longer useful for the Jews, they are not useful for us today for giving us salvation. It is still good to work for God, but it won't get us to heaven. The Gentiles were not saved by the works of the Law but by the grace of God through their faith.
In Romans 11:11-15 Paul is thankful for the Jews for it was through the Jewish people that Christ came to be the Savior of the entire world - both Jew and Gentile. And Paul had been called to be an apostle or missionary to the Gentiles who before had had no general hope of salvation, many being lost in worship of false gods and idols as were prevalent in the Middle East, Greece and Rome.
Paul's entire work was done trying to get first the Jews in a community but after that all of the Gentiles to accept Christ as Savior and worship God with him in spirit and in truth. But at the end, he pointed out that just because many Jews had been broken off from the holy root of God because of their unbelief in Jesus Christ as their Messiah, that this didn't have to be a permanent condition for them any more than it did for the Gentiles.
In Romans 11:16-24 Paul applies the Gentile state and the Jewish state to an olive tree. Those who have rejected Christ have been cut off from the root and are withering on the ground. Gentiles which had no part in salvation through the Jewish faith have been grafted into the olive tree and are living and taking nourishment from God through the roots of the tree.
Paul warns them not to be proud or boastful that they have been added into the tree at the expense of the Jewish people who failed to accept Christ. Those broken branches could be easily grafted back in and would thrive more fully because they were naturally part of the tree. But they have to make the choice to accept Jesus' salvation, just like the Gentiles do.
The goodness of God makes it possible for both the natural branch to return by accepting Christ and for a Gentile branch to be grafted on. Once the grafting is complete, all would grow healthy and live as part of the olive tree. The only place of death was to stay on the ground and not partake of the plan of God through Christ.
The remainder of the chapter (Romans 11:25-36) declares the greatness of God and His mercy in providing a path for salvation for the Jews in the Old Covenant and a path for salvation for all in the New Covenant. It is God's desire that all be saved.
Just because the Jews had chosen to ignore Christ at this time and the Gentiles had been chosen to have a chance at salvation, Paul speaks of the future time at the second advent and declares that there will be a time in the future when the Jewish state will once again become preeminent and the Gentile nations will take a back seat again. God will never forget His people. (Zechariah 12:10-13:1)
Of all the concepts we could take from this chapter, the main things are this. We need to be grafted into God's living tree. We cannot survive on our own and our own attempts at works are useless. We depend on the grace and mercy of God for all we are, have, and do. Let us choose to serve Him and listen for what He wants each of us to do. Perhaps not listening will not have as dire a consequence as for the Jews who rejected their Messiah or for the Gentiles through history and in our day who reject Jesus Christ. But God's desire is that all would be saved, and I pray that He will help us to do our part.