The dialogue continues. It is clear the conversation being reported by Nephi is one where both the Son and the Father spoke to Nephi, and contributed to the dialogue. A question was posed about whether Nephi heard this in connection with his vision of Christ's mortal baptism by John the Baptist. He certainly beheld that event. (1 Nephi 11: 27.) However, the testimony and teaching of both the Father and Son regarding baptism, as reported by Nephi in this final sermon, are separate from that event. They are an independent revelation and explanation to Nephi, where both the Father and Son taught the importance of baptism.
The Lord also knows whether it is in you to "endure to the end." Whether the end has come is irrelevant to Him. He beholds all things, past, present and future. (D&C 130: 7.) Therefore, He knows if you are willing to "endure to the end" before your life has been lived.
Enduring to the end, or the fixed purpose to always serve God so that you may always have His spirit to be with you, is essential to salvation. You claim this is your determination every time you take the sacrament. (D&C 20: 76-79.) Whether you take this commitment seriously or not determines whether you are destined for salvation or not. It also determines if you are qualified to receive His personal ministry and comfort.
The Father declares: "Yea, the words of my Beloved are true and faithful." The reason Christ is the Father's "Beloved" is directly related to His words being "true and faithful." That is, Christ only does and says what He knows represents the Father's will. He has done this "from the beginning." (3 Nephi 11: 11.) He represents the "Word" of the Father because you can find in Christ's words and deeds the very word of the Father. (D&C 93: 8.)
It is this that qualified Christ to be the Redeemer. His words are faithful and true. So are Nephi's. The words are the Lord's though they were delivered by a man.
Nephi, having been true and faithful in all things, was able to converse with the Father and the Son through the veil and receive from them further instruction, counsel, warning, and comfort because of the things he learned. This is the pattern for all of us. This is the culminating message of the Gospel of Christ.