Nephi declared at the beginning of the last chapter (2 Nephi 31:3) that he delighted in plainness. Here he reiterates that he has spoken plainly. If we do not understand, it is not because he did not explain as clearly as he could, but because we do not have the Spirit assisting us. It is because “ye ask not, neither do ye knock.”
This leads Nephi to reiterate what he had just said in verse 3. There he indicated that the words of the Messiah would tell us all we need to do; here it is the Holy Spirit that will show us. That slight difference creates a parallelism that expands on the meaning. The scriptures may tell, but the Spirit shows. We not only need the scriptures, but we also need the Spirit to help us understand and apply the scriptures.
When Nephi declares “this is the doctrine of Christ,” it is the conclusion to the discussion he began in 2 Nephi 31:2 where he indicated that “I must speak concerning the doctrine of Christ.” He declared what he would do, and now declares that it has been done.
This process of baptism, repentance, and enduring to the end is the short summation of all of the doctrine of Christ. The doctrine of Christ is to reach the end of the way, and that end is eternal life. There is no other way to accomplish that purpose. Therefore, “there will be no more doctrine given until after he shall manifest himself unto you in the flesh.” This is sufficient for those who live under the law of Moses to understand how they should live until such time as Christ will provide more instruction. Reiterating his other theme, Nephi declares that in the future, there will be more doctrine, but that it will still show what we should observe to do.