Narrative analysis: It is very likely that Nephi's brethren know nothing about Nephi's recent vision, and the promise to Nephi that he would rule over them. It is also quite unlikely that the brothers knew of Nephi's impassioned vow to Lehi that he knew that the Lord would prepare the way for them. Nephi's oath "As the Lord liveth, and as we live" was a powerful commitment. Smith's Bible Dictionary presents the following information on oath-taking:
"The principle on which an oath is held to be binding is incidentally laid down in Hebrews 6:16 as an ultimate appeal to divine authority to ratify an assertion. There the Almighty is represented as promising or denouncing with an oath, i.e. doing so in the most positive and solemn manner. On the same principle, that oath has always been held most binding which appealed to the highest authority, both as regards individuals and communities. As a consequence of this principle, appeals to God's name on the one hand, and to heathen deities on the other, are treated in scripture as tests of allegiance" ("Oath", in Smith's Bible Dictionary. Fleming H. Revell Company, 1970, p. 462).
By invoking the name of the Lord, Nephi is binding himself with the strongest of oaths. His subsequent arguments serve to convince his brethren to accompany him. There is no record that the brothers repeated the oath, even though they did participate one more time.