In the account of the Lord revealing himself to the brother of Jared, we find the Lord saying, And never have I showed myself unto man whom I have created, for never has man believed in me as thou hast" (Ether 3:15). The Book of Mormon student might be confused about such a statement in light of the biblical accounts of the patriarchs. However, Kent Jackson notes that when the Lord appeared in ancient times, he did so as the Father, and when he gave revelation to prophets, he spoke of the mortal mission of Jesus Christ in the third person, with the words of and from the perspective of God the Father, as though Jesus Christ were someone else… . The appearance to the brother of Jared is the first recorded manifestation of Jehovah in which he appeared and identified himself as the Son
The uniqueness of this situation lies in the fact that Jehovah appeared to Mahonri Moriancumer in his role as Jesus Christ -- rather than as the Father. Never before, as far as we can tell from the scriptures, had Jesus Christ shown himself unto man. (and interestingly, nowhere else in the scriptures do we have a clear example of Jehovah appearing as Jesus until his coming in the flesh. As Moroni reported, “Having this perfect knowledge of God, he could not be kept from within the veil; therefore he saw Jesus” (Ether 3:20. To the brother of Jared, Christ revealed his complete nature: God who would become Man--Jehovah, the Father, who would become Jesus, the Son.
Perhaps the unprecedented nature of this appearance is a reason why the Lord commanded that the account not be made known in the world until after his mortal ministry (Ether 3:21). [Kent P. Jackson, “Never Have I Showed Myself Unto Man,” F.A.R.M.S., 1991]
Ether 3:15 Seest thou that ye are created after mine own image? ([Illustration] Chart: “Does Christ Have a Body?” Source: Susan Easton Black, Finding Christ through the Book of Mormon (Salt Lake City: Deseret Book, 1987), 52-56. [John W. & J. Gregory Welch, Charting the Book of Mormon: Visual Aids for Personal Study and Teaching, F.A.R.M.S., Chart #52]