Paul, a Jew, was an apostle to the Gentiles, but he loved his Jewish people. He prayed that his Gentile ministry might make the Jews jealous enough to repent and return to God, like a dead branch coming to life after getting grafted to an olive shoot. The root of Israel is the Messiah (Isa 11:1). The olive tree is the people of God. When branches are connected to God and the Messiah, they are alive. When they are cut off from God, they are dead. Paul prayed for Israel to recover her life and mission.
Paul is writing to Gentile believers. He wants them to have a sense of history. They should not be arrogant; they should fear God. Israel was cut off because of pride and unbelief. Gentiles are included by God's grace because of their faith alone. They derive their nourishment from being attached to the root, by being a part of God's people and his history. If Israel repents and believes, she can again be grafted into God's history.
Application: Lord, by grace you grafted me into Jesus and into your redemptive history. Help me to stand.
One Word: Stand by faith, connected to the root