Nephi speaks again with the Father's words: "Wherefore, if ye shall press forward, feasting upon the word of Christ, and endure to the end, behold, thus saith the Father: Ye shall have eternal life." (2 Nephi 31: 20.) Having this assurance from the Father gives Nephi's words an additional certification of authority. We have so few quotes from the Father recorded in scripture that Nephi's quotes from Him give a dimension we would not otherwise have.
We cannot take time to elaborate fully, but it is important to note that what Nephi gives us here is an unprecedented account of statements from the Father. Moroni will later testify to the overall record in the Book of Mormon as true because of three witnesses: The Father, the Son, and the Holy Ghost, who have all testified to the record's truth. It is here, with Nephi, where we find the Father's testimony of these truths for the first time in the record. We will encounter it again when Christ appears, and the Father introduces Him to the Nephites. As a result, we have more testimony, and a larger survey of the words of the Father within the Book of Mormon than any other volume of scripture. Anyone interested in eternal life should value this record above all others.
Nephi recognizes that most who hear these words will be skeptical. Rather than accept these things, people will generally hesitate and criticize new revelation. He gives some advice about how to overcome this skepticism. He tells us to use prayer to solve our doubts. You will recall he did this earlier. He was able to accept his father Lehi's teachings because of prayer and softening of his heart. He commends this to us.