1 Nephi 15:17-18

In verse 17, Nephi is explaining to his brothers that their seed will not be grafted back into the olive tree until after they had been scattered by the Gentiles. We have seen that this is true. The Gentiles have scattered the seed of Nephi and his brothers. We have seen this with the settling of the New World by European countries. The natives were conquered. However, we now see that they are receiving the gospel. They are a believing people and the Church is thriving among them. This flourishment is a manifestation of the power of God. Verse 17 also says that this same success will happen when Jesus is on the earth and that it is this success that shall be the very cause he will be rejected of the Jews, I think, but I'm not sure.

In the next verse, Nephi adds that it will not only be their seed that will be converted, but all of the house of Israel. He testifies that that this is due to the Lord's promise to Abraham saying that through him all the kindreds of the earth shall be blessed.

I thought that this thought from the Book of Mormon Institute Manual was helpful for these verses:

"The Book of Mormon writers often used the term Jew in a broader sense than we use it today. By Lehi’s time the Ten Tribes had been lost and the kingdom of Judah was the only known group of Israelites, so the term Jew sometimes meant more than just a member of the tribe of Judah. Throughout the Book of Mormon we find this broad usage where often the world is divided into Jews and Gentiles (see 1 Nephi 13:42, 2 Nephi 27:1, Mormon 7:8). In these verses Nephi clearly foresees the mission, trials, scatterings, and destiny of the tribes of Israel."