The Pnei Yehoshua (Kiddushin 30a) quotes the Zohar saying that there are six hundred thousand letters in the Chumash. He then explains, quoting from the Shaloh Hakadosh, that the idea the Zohar is trying to convey is that each Jew has a share in the Torah. At the conclusion of the Shmone Esrei we always offer a prayer that Hashem should give us our share in the Torah. In the sefer Ma'alos Ha'Torah (authored by R' Avrohom, the brother of the Gr"a) the Gr"a is quoted as having explained that tefillah to mean that in heaven it is determined what original ideas in Torah each Jewish person should come up with and we pray to Hashem that we should succeed in developing those ideas that were intended for us to develop.
The Torah prohibits moving over the fence separating one's field from a neighbor's field and thereby stealing part of the neighbor's property. The Torah restricts this special prohibition to Eretz Yisroel. If one steals an automobile, whether in Eretz Yisroel or in any other part of the world, the Sifrei says that he violates lo tigzol. If one moves over the fence in chutz la'aretz, he also only violates lo tigzol but if one moves over the fence in Eretz Yisroel, in addition to the violation of lo tigzol one also violates this prohibition of ha'sogas gevul. This prohibition applies only in this very narrow case.
The Sifrei, however, adds a striking comment: this limited prohibition also applies to one who incorrectly presents the views of Rabbi Eliezer in the name of Rabbi Yehoshua or the views of Rabbi Yehoshua in the views of Rabbi Eliezer. When one knowingly misrepresents the author of a halacha this somehow is similar to one who moves over the fence in Eretz Yisroel. What in the world do these two situations have in common?
The Rambam (Hilchos Terumos, chapter 1) quotes an expression from the Sifroh that almost all the agricultural mitzvos only began to be observed after Yehoshua bin Nun conquered Eretz Yisroel and divided it first amongst the shevotim then amongst the mishpachos and then amongst the yechidim. Tanach tells us that the conquest of Eretz Yisroel took a full seven years, and we have an oral historical tradition that the chalukah, the dividing up of the land, took another seven years. The fifteenth year was the first time that the Jewish people fulfilled the mitzvah of teruma, etc. The first shmitah was the twenty-first year after they crossed over the Yarden and the first yovel was the sixty-fourth year. The striking expression quoted by the Rambam from the Sifroh is that for the complete kedusha of Eretz Yisroel to take effect it was required that each and every individual person recognize what was his share of the land. Perhaps the Sifrei's idea that one who misidentifies the author of a specific halacha is also in violation of ha'sogas gevul is to be understood as follows: just as the complete kedusha of Eretz Yisroel only sets in when each and every individual recognizes which is his share, and therefore if someone moves over the fence this takes away partially from the kedusha of Eretz Yisroel, similarly each individual person has his share in the Torah, and the complete kedusha of the Torah is realized when each halacha is properly attributed to the tanah who authored it. Therefore, if one will misidentify a din of R' Yehoshua and attribute it to R' Eliezer, this too takes away from the complete kedusha of the Torah because we are lacking kol echod v'echod makir es chelko.
In Yiddish folklore, it is well known that the following question was raised: when B'nei Yisroel left Mitzrayim and took a census of the nation, there were 600,000 people who were born Jewish. But in addition to those who were Jewish from birth, there were many non-Jews who came along to convert. If we have 600,000 letters in the chumash to represent that every single Jew has a share in the Torah, shouldn't there be something to represent the idea that all of those who convert are given a new Jewish neshama and each of them also has a share in the Torah? So in Yiddish folklore they refer to a possuk that appears in the tochacho in this week's parsha: "ha'ger asher b'kirbicha ya'aleh olecho ma'alah moloh, v'atoh teireid matoh motoh". The simple meaning of the possuk is that the non-Jews will be very successful in their careers and the Jews will be failures. According to the simple meaning of the possuk, the work "ger" refers to the non-Jewish strangers who happen to live in Eretz Yisroel. But the Gemara tells us that the famous Rabbi Akiva was a descendent of geirim, and he was of the opinion that we can derive halachos not only from the words of the Chumash but even from the tagim which appear on the top of the letters. So in accordance with Yiddish folklore, the possuk is understood to refer to the geirim who are converts; their share in the Torah is not in the letters, because there are only six hundred thousand letters, but rather is in the tagim.
Every Jew has a share in the Torah whether he was a Jew from birth or he converted later on in life, and every day when we say, "v'sein chelkeinu b'Torasecha" we are praying that Hashem should please give us the ability to develop those insights of the Torah that were intended for us.