The book of 3 Nephi ends with the most extraordinary and intimate interactions between Jesus and his twelve disciples. Rarely are we allowed to part the heavenly curtain and get a glimpse of such sacred moments. Why might Nephi and Mormon have wanted to share with all readers this parting request and gesture?
We don’t know how old these disciples were when the made the request that could enter into Christ’s kingdom when they had reached what they called the “age of man,” which appears to be the “the age of seventy and two years” (3 Nephi 28:2–3). Assuming that they were at least young adults at the time of the birth of Jesus, they would now have been about fifty to sixty years old at this time, and they would have been growing more aware of their own, inevitable, deaths. And indeed, by AD 100, the nine regular disciples had all died (4 Nephi 1:14).
Apparently, they were aware that some people, when they die, go quickly into the spirit Paradise, while others go for a time into spirit Prison, where they may learn and improve in preparation for their day of judgment. Mormon may have wanted us to know that.
But even more, all of 3 Nephi 28 deals with the power of Jesus over death. He granted requests regarding the timing and transition of nine of the disciples into life beyond death. He sensed the desires of three others to never taste death but to remain as special servants to assist with the establishment of the Kingdom of God on earth. In all of these cases, Jesus controls death. He voluntarily had given up his own life and handed his Spirit over to the Father. He had conquered death and had opened the gates of hell. As evidence that he indeed had power over mortality, Jesus granted and carried out these righteous and appropriate requests made by his disciples at a time when it was needed to be sure that the work of the Kingdom would endure (3 Nephi 28:9; compare D&C 7).
All of 3 Nephi can be seen as a book of Jesus’s conquest of death. He controlled the timing of his birth. He controlled the destructions and deaths at the time of his crucifixion. He took up his gloriously resurrected body. He had power over his coming and going. Seeing all of 3 Nephi as a temple text, one remembers that the final sealing ordinance in the temple pertains to promises of coming forth in the resurrection, overcoming death, and going forth into eternal life. And thus, it makes sense that 3 Nephi should end talking about and giving actual reports of overcoming death. As 3 Nephi is the Holy of Holies of the Book of Mormon, it culminates here on its holiest pinnacle of the mountain of the Lord at Heaven’s gate.