In several places in the Book of Mormon the house of Israel is likened to an olive tree. In this analogy, some of the natural branches of the olive tree (the direct descendants of the house of Israel) are grafted or planted in other parts of the vineyard (in other words, they are led to other parts of the earth). However, Nephi prophesies that in the last days these natural branches of the house of Israel "shall be grafted in, being a natural branch of the olive-tree, into the true olive-tree." (1 Nephi 15:16. Italics added.) This evidently means that the direct descendants of Israel are going to be brought to a knowledge of the true covenants that the Lord made anciently with the house of Israel.
Essentially this same idea is expressed in 1 Nephi 10:14, where Nephi says that in the last days "the natural branches of the olive-tree, or the remnants of the house of Israel, should be grafted in, or come to the knowledge of the true Messiah, their Lord and their Redeemer." (1 Nephi 10:14.)