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Source:Roper et al:“If there be faults:BYU Studies 53:3:Nephi had been a Jew politically, but his ancestors were of Manasseh
Roper et al.: "Nephi had been a Jew politically, but his ancestors were of Manasseh"
Matthew Roper, Paul Fields, and Larry Bassist: 
[W]e find nothing inconsistent about Nephi’s use of the term Jew. By the time of the divided kingdom, “the term ‘Yehudi’ applied to all residents of the Southern Kingdom, irrespective of their tribal status.” The translators of the King James Version of the Bible saw nothing wrong in rendering the term Jew in passages describing the last days of Judah, including within the book of Jeremiah, which was written by Lehi’s contemporary (2 Kgs. 16:6; 18:26, 28; 25:25; Isa. 36:11, 13; Jer. 32:12; 38:19; 40:11–12, 15; 41:3; 44:1; 52:28). Nephi says he has charity for the Jew and adds, “I say Jew, because I mean them from whence I came” (2 Ne. 33:8)....the phrase makes sense in context. Nephi had been a Jew politically, but his ancestors were of Manasseh with roots in the Northern Kingdom (1 Ne. 6:2; Alma 10:3). The fact that the Jerusalem elite had tried to kill him and his family, forcing them to flee their home, makes Nephi’s language understandable.
- Matthew Roper, Paul Fields, and Larry Bassist, "'If there be faults': Reviewing Earl Wunderli’s An Imperfect Book," BYU Studies Quarterly 53, no. 3 (2014) 124.
- Raphael Posner, “Jew,” Encyclopaedia Judaica (Jerusalem: Keter Publishing House, 1996), 10:21; compare Solomon Zeitlin, “The Names Hebrew, Jew and Israel: A Historical Study,” Jewish Quarterly Review 43 (April 1953): 365–79; Solomon Zeitlin, “Who Is a Jew? A Halachic-Historic Study,” Jewish Quarterly Review 49 (April 1959): 241–70. Cited in Roper, Fields and Bassist, "If there be faults", fn 4.