The theme of these verses is repetitious in the Book of Mormon, and most appropriately so. The Book of Mormon is the book ordained in the councils of heaven by which to gather Israel from the “four quarters of the earth.”
The great message and testimony of the Book of Mormon is that all who believe on Christ as the Son of God and keep his commandments shall have eternal life. That being the message and the book being the messenger, then it ought to be clear that the gathering is, and must always be, first to Christ, and that no assembling of any peoples in any lands is of any lasting moment unless they have first embraced the doctrine and testimony of Christ as taught in the Book of Mormon.
The testimony of these verses is that the tribe of Joseph, which along with all the tribes of Jacob has been scattered among all people throughout the earth, will in the last days be restored to that covenant relationship known to their ancient fathers. That is, they shall come to “know their Redeemer, who is Jesus Christ, the Son of God.”