The Miracle of Restoration
"Even they, if they do not continue in their unbelief, will be grafted in, for God has the power to graft them in again" (v. 23).
"All things in Scripture are not alike plain in themselves, nor alike clear unto all: yet those things which are necessary to be known, believed, and observed for salvation, are so clearly propounded, and opened in some place of Scripture or other, that not only the learned, but the unlearned, in a due use of the ordinary means, may attain unto a sufficient understanding of them." That classic statement from the Westminster Confession of Faith (1.7) summarizes what theologians call the perspicuity, or clarity, of Scripture. God has revealed His gospel so plainly in His Word that anyone who reads or hears the Bible attentively can understand it. At the same time, the Bible consists of more than the basic message of salvation. Some parts of it are more difficult to understand than others, and some passages require a great deal of studious effort to interpret rightly (2 Peter 3:15-16).
This truth cautions us against drawing conclusions about metaphorical passages too quickly. If any text requires diligent interpretive work, it is a text full of symbolism. Yet not everyone does the hard work necessary. Countless books, articles, and websites take Paul's warnings in Romans 11 about being broken off from God's people Israel and the need to stand firm in faith as admonitions proving that regenerate people can lose their salvation.
Whatever else we say about Romans 11:16-24, we press the olive tree metaphor too far if we conclude that Paul is teaching that regenerate people can fall away finally. First, Romans 8:29-30 tells us plainly that everyone whom God regenerates ("calls") will also be glorified. Second, while Romans 11 has import for an individual's salvation, the Apostle focuses on the place of the corporate body of ethnic Israel in the kingdom of God. He is using the metaphor to make a point about the Lord's ongoing plan for the Jews and not to give an in-depth analysis as to whether the regenerate can commit final apostasy. Paul is speaking in corporate categories. The Jews have been cut off—in large measure but not in their entirety—so that the Gentiles can be grafted in—in large measure but not in their entirety.
Since He is the Creator, however, God can do what no horticulturist can do and re-graft broken-off branches back into the tree (vv. 23-24). The Lord is able to re-graft the Jews back into the olive tree Israel—all true believers in God through Jesus—by converting them to Christ. Gentiles should not think that all Jews will remain hardened for all time, for the Lord is able to do a miracle and bring them back into the fold.
Coram Deo
Scripture teaches that the elect can never fall away finally, but it also tells us that the Lord works in and through our decisions to keep us from such a fall. The Bible's warnings about falling away are real; it is just that we know the Spirit uses them in the hearts of the elect to make us persevere. Do you want assurance that you are elect? Consider how you respond to these warnings. If you take them seriously and seek the Lord's face that He would preserve you, then you are His child.