Emphatically, in this very first chapter, Nephi states the purpose of his record: to teach the doctrine of Christ. And significantly, in this very first chapter, Nephi also records the vision in which Lehi learns of the coming of the Messiah (as Lehi repeatedly calls Him, 1 Nephi 1:19, 10:4, 5, 7, 9, 10, 11, 14, 17) and the Twelve.
What did the Twelve do? They went forth and followed the Messiah. As Nephi explained that "[T]he twelve came down and went forth upon the face of the earth, and the first came and stood before my father." The Twelve were sent throughout the whole earth. What do the Quorum of the Twelve do today? They oversee all the affairs of the world. But the One came down and spoke directly to Lehi. This was no small thing.
There is one preposition that needs to be pointed out in these passages. Lehi "thought he saw God sitting upon his throne, surrounded with numberless concourses of angels in the attitude of singing and praising their God." Surrounded with. What is the difference between "with" and "by"? It is significant, because it may signal that God is with them. Most people would say "surrounded by," but Lehi says surrounded "with" numberless concourses of angels. "With" may mean a lot more than "by." This small, unusual word choice depicts something about who God is. He is not surrounded by concourses because He needs to show off. He is surrounded with them because He is an invested partner in every one of those individual’s salvation. I think that’s a beautiful revelation.
Next, this glorious being, whose brightness was above that of the sun at noonday, even the Lord Jesus Christ, came down. What did He do? He gave Lehi a book. What was the importance and significance of the book? What is the significance of the Book of Mormon? If you look at the establishments of the major religions in the world, they all begin with a book. Books are essential in establishing doctrine and religion. There are books on earth and books in heaven, and as is seen here in Lehi’s vision, heavenly decrees will be announced in books, our deeds will be recorded in books of life, and by the words given to us by God we will be judged (Mosiah 3:24; Moroni 10:27).
Welch, John W. "The Calling of Lehi as a Prophet in the World of Jerusalem." In Glimpses of Lehi’s Jerusalem, edited by John W. Welch, David Rolph Seely and Jo Ann H. Seely, 421–448. Provo, UT: Foundation for Ancient Research and Mormon Studies, 2004.