As part of the latter-day gathering of Israel, The Church of Jesus Christ of Latter-day Saints embraces the perspective that it is largely of the descendancy of Ephraim, son of Joseph. 

1 Chronicles 5:1–2 tells us that “though Judah became prominent among his brothers and a ruler came from him [that is, David], the birthright belonged to Joseph.”

The concept of “birthright” is an important one. One prominent biblical dictionary explains that birthright is:

The right of the firstborn son of the mother of the household to be its heir. This heir received twice the property as did the others (Deut. 21:17; MAL B:1). . .Households were patrilineal: members received social status from the father; only he designated heirs. Some designated “heirs” or “firstborn” (Heb. ben) by birthright, others by achievement. Using birthright reduced competition between the mothers and sons of the household. In the stories of Isaac and Rebekah (Gen 21:1–45) and the Code of Hammurabi, however, achievement designates a more competent heir than the birthright male, which helped the Hebrews survive in an unstable world.⁸⁴

In the case of Joseph, then, he won his “heirship” through competency rather than strictly birthright. His status as the more competent heir and reception of the “birthright” is important, though, since that would make him heir to Israel.

In the latter days, Latter-day Saints have claimed to possess this birthright and, with it, the right to preside over and effectuate the gathering of Israel and the creation of the Lord’s Kingdom on the Earth prior to His Second Coming. This scripture in 1 Chronicles, then, is important for establishing Latter-day Saint identity. As explained by the Latter-day Saint Bible Dictionary:

Ephraim was given the birthright in Israel (1 Chr. 5:1–2; Jer. 31:9), and in the last days it has been the tribe of Ephraim’s privilege first to bear the message of the Restoration of the gospel to the world and to gather scattered Israel (Deut. 33:13–17; Doctrine & Covenants 64:36; 133:26–34). The time will come when, through the operation of the gospel of Jesus Christ, the envy of Judah and Ephraim shall cease (Isa. 11:12–13).

1 Chronicles and Jeremiah’s witness of Joseph and Ephraim as recipients of the birthright and modern revelation’s claim for the same privilege helps to establish The Church of Jesus Christ of Latter-day Saints as the Lord’s kingdom: His “only true and living church upon the face of the whole earth” (Doctrine & Covenants 1:30).