In choosing “to preach the word of God” (v. 4), Nephi was following the same course as Alma, the first chief judge, although no mention is made of his doing as Alma did. Alma had resigned in the ninth year of his reign because he saw “no way that he might reclaim them save it were in bearing down in pure testimony against them” (Alma 4:20). Nephi’s reason was similar but influenced by his father’s admonition to both him and his brother Lehi (Helaman 5:5). Thus Nephi had help in trying to save his subjects from destruction (v. 4).
Father Helaman’s desire to “declare unto the people these words” (v. 6) is not clear. He probably had reference to the words of the commandments, as indicated by the punctuation of the sentence. On the other hand, Helaman may have meant for them to declare the reason he had named them Nephi and Lehi (vv. 6–7). Regardless, the best way to teach is by personal example. As the Apostle James admonished: “be ye doers of the word, and not hearers only” (James 1:22). Furthermore, all people need to have heroes.
To lay up treasures in heaven is a principle taught in the Sermon on the Mount in the New Testament (see Matthew 6:19–21). That this principle was taught earlier in the Old Testament is evidenced by Helaman teaching the principle to his sons Nephi and Lehi (Helaman 5:8). Helaman had a copy of that part of the Old Testament inscribed on the plates of brass, and he was probably quoting from a plain and precious part of the text that is now lost from the Old Testament (see 1 Nephi 13:26–29). Helaman equates the laying up of treasures in heaven with eternal life (v. 8). In the Sermon on the Mount, Jesus is making a similar comparison, but he does not speak as directly as did Helaman. Someday we will have those plates of brass and will be able to prove that this teaching was once in the Old Testament.