Jehovah
Blessed art thou, Nephi, for those things which thou hast done; for I have beheld how thou hast with unwearyingness declared the word, which I have given unto thee, unto this people. And thou hast not feared them, and hast not sought thine own life, but hast sought my will, and to keep my commandments. Helaman 10:4–6
A voice comes to the discouraged prophet and speaks as God in the first person. This is the Lord of Israel, the premortal Christ, who knows Nephi's unwearied service and blesses him forever.
How we know: the verse itself names Him
