The final step of the plan of salvation is to endure to the end (v. 15). However, there is another consideration. JST, John 1:19 says: “And no man has seen God at any time, except he hath borne record of the Son; for except it is through him no man can be saved.” When Nephi heard the voice of the Father is not certain. It may have been as he was writing this record, or it may have been during the vision of Jerusalem when he saw the prophet baptizing the Lamb of God.
This is the only account in the present-day scriptures where the Father does more than introduce the Son, particularly if the voice of the Father was actually heard by Nephi. Nephi said he heard “a voice from the Father” (emphasis added). Therefore, it could be something the Father said but was quoted by the Son. This happened when Jesus visited the Nephites (see 3 Nephi 15:16; 16:7–8, 10, 14). The voice of the Son and the Father was heard together twice (vv. 11–12 and 14–15). The last time, “Yea, the words of my Beloved are true and faithful,” confirms what the Son had just said. Regardless, all of the statements in 2 Nephi 31 that are attributed to the Father bear record of the Son and what he taught in the plan of salvation.
This whole chapter is based on Nephi’s experience of being shown the birth and ministry of Christ many years earlier (1 Nephi 11).