Romans 11:21

For if God spared not the natural branches, neither will he spare thee.

In the event that Gentiles should manifest the same qualities of unbelief and obduracy which marred the life of fleshly Israel, the consequences for them will be the same, there being here another hint of the superiority of the Jews, as represented in the degree of preference pertaining to the natural branch over the wild branch. This verse shouts the conditional nature of God's favor. Far from there being any such thing as an everlasting decree that this or that shall happen, people are endowed with freedom of the will to act as they choose to act; and the immutable election is to the effect that whichever way they act will determine their destiny. This verse shows that exactly the same principles of God's judgment are applied to Jews and Gentiles alike with impeccable impartiality. It is God's intrinsic righteousness, the basic theme of Romans, which required Paul to spell out the immutable quality of the eternal justice of the Creator, as in this passage.