In Genesis 48:19, the patriarch Jacob is giving a blessing to Joseph's sons sons, Ephraim and Manasseh, and responds to Joseph's objection about treating the slightly-younger Ephraim as if he were the firstborn instead of Manasseh:
And his father refused, and said, I know it, my son, I know it: he also shall become a people, and he also shall be great: but truly his younger brother shall be greater than he, and his seed shall become a multitude of nations.Significantly, it is Ephraim that is associated with "m'loh ha goyim," the fullness of the Gentiles/multitude of nations.
Here is Paul's use of the term in Romans 11:25:
For I would not, brethren, that ye should be ignorant of this mystery, lest ye should be wise in your own conceits; that blindness in part is happened to Israel, until the fulness of the Gentiles be come in.Earlier in this chapter, he discusses the gathering of Israel and uses the analogy of grsfting in olive branches. From my LDS perspective, I read Paul as saying that the redemption of Israel will not be complete until a future time when the fullness of the Gentiles comes, which I take to be the Restoration of the Gospel among the Gentiles.
Now consider the related Book of Mormon passages. Nephi in First Nephi 15:13-14, links "fullness of the Gentiles" to the Restoration and the gathering of Israel:
13 And now, the thing which our father meaneth concerning the grafting in of the natural branches through the fulness of the Gentiles, is, that in the latter days, when our seed shall have dwindled in unbelief, yea, for the space of many years, and many generations after the Messiah shall be manifested in body unto the children of men, then shall the fulness of the gospel of the Messiah come unto the Gentiles, and from the Gentiles unto the remnant of our seed --The term is used by Jesus Christ in Third Nephi 16:4, again in the context of gathering the scattered remnants of Israel in the last days:
14 And at that day shall the remnant of our seed know that they are of the house of Israel, and that they are the covenant people of the Lord; and then shall they know and come to the knowledge of their forefathers, and also to the knowledge of the gospel of their Redeemer, which was ministered unto their fathers by him; wherefore, they shall come to the knowledge of their Redeemer and the very points of his doctrine, that they may know how to come unto him and be saved.
4 And I command you that ye shall write these sayings after I am gone, that if it so be that my people at Jerusalem, they who have seen me and been with me in my ministry, do not ask the Father in my name, that they may receive a knowledge of you by the Holy Ghost, and also of the other tribes whom they know not of, that these sayings which ye shall write shall be kept and shall be manifested unto the Gentiles, that through the fulness of the Gentiles, the remnant of their seed, who shall be scattered forth upon the face of the earth because of their unbelief, may be brought in, or may be brought to a knowledge of me, their Redeemer.One can easily argue that the usage in First Nephi is "plagiarized" from Romans 11, where grafting an olive branch and "fullness of the Gentiles" are both invoked. Or one can understand that both concepts date to much earlier times, with common ancient origins being at play rather than plagiarism (see The Allegory of the Olive Tree, ed. Stephen D. Ricks and John W. Welch (Salt Lake City: FARMS and Deseret Book, 1994)).
5 And then will I gather them in from the four quarters of the earth; and then will I fulfill the covenant which the Father hath made unto all the people of the house of Israel.
Regarding the nations/Gentiles ("goyim"), the link to Ephraim in Genesis and in LDS writings can be puzzling because we tend to associate Gentiles with non-Hebraic peoples. But that term may have a couple different usages. Sometimes it clearly refers to the pagan nations, but other times it can refer to nations descended from Israel or including Israelites. For example in "The 'Gentiles' in God's Plan" (a site of the Canadian British-Israel Society), there is further discussion of the scope of meanings of the term "Gentile":
It is a widely popular view today that the word, 'Gentile,' in our English Bible translations can only refer to non-Israelites, yet the facts prove conclusively otherwise. The following information from leading Bible reference works proves that this word refers instead to 'nations,' representing sometimes the dispersed house of Israel, sometimes non-Israelites, and sometimes both, as in 'all nations'. The word, "Gentile," is an English language substitution for the original New Testament Greek words, 'ethne,' (singular) or 'ethnos,' (plural) and the Old Testament Hebrew words, 'goy' (singular) and 'goyim' (plural).John Tvedtnes makes some similar points in his chapter, "Who Are the Gentiles" in The Most Correct Book (Salt Lake City: Cornerstone Publishing, 1999, pp. 29-36). He suggests that the mission of taking the Book of Mormon to "Jew and Gentile," according to the cover page, and of taking it to the remnants of Israel among the tribe of Joseph, may really be a unified mission, for "the Gentile" may refer to the tribe of Joseph. The "Gentiles" may be the Ephraimites - after all, the Gospel was restored through Joseph Smith, a "Gentile" and yet an Ephraimite of the tribe of Joseph.
In teaching that Gentiles can only be non-Israelites, it is held by some that Christ in Matthew 10:6 ("Go not into the way of the Gentiles") was commanding against witnessing to non-Israelites! But in so doing, this makes the Bible contradict itself, for in Matthew 24:14, Christ said the exact opposite: "This gospel of the kingdom must be preached in all the world as a witness unto all nations [ethnos/Gentiles]." Which is it? Are the "ethnos," or "Gentiles" to hear the Gospel or are they not?
The answer is provided by Messianic Jewish Bible scholar, David H. Stern, in the "Jewish New Testament Commentary," which points out that the word, Gentile has two meanings. (page 531) It was used in a "neutral" sense of any particular nation or nations (which ones to be determined by context), or a "pejorative overtone" as "pagan, heathen." Therefore, it can sometimes refer to "non-Israelites," but not exclusively. Sometimes the singular form, ethne, meant the Jewish nation, and the plural form, ethnos, was used to refer to non-Jewish nations, but again not exclusively. The Jewish nation of Christ's day included large numbers of Israelites, so if the Greek, ethne, and Hebrew, goy, ever refer to the Israelite tribe of Judah, one cannot say that it means non-Israelites!
Tvedtnes suggests that the idea that Gospel will not go forth to the Jews until it has gone to all other nations may be incorrect, since the "Gentiles" to whom the Gospel must go forth already includes those of Israel, especially Ephraim.
In any case, I am intrigued by the "fullness of the Gentiles" concept that stems from Genesis 48 and its implications for the Book of Mormon and the Restoration of the Gospel in the latter-days.