I have just been re-reading 3rd Nephi, I especially like the direct words of the Saviour. I am extremely concerned about one point. The Lord Jesus Christ had ALL of the Nephite/Lamanite survivors praying earnestly on their knees and he moved off a little to pray privately to Father in Heaven and we read the words of his prayers. Who recorded them for the Book of Mormon?
The book of Third Nephi was written by Nephi who was the grandson of Helaman. It was Mormon, of course, who abridged Nephi’s record, and Mormon’s abridgement is what we have in the Book of Mormon. Not only did Mormon abridge the record that was inscribed on the Large Plates of Nephi, but he frequently made comments on the scene. For instance, the entire 12th chapter on 3 Nephi are Mormon’s comments. These are characterized by thus we can behold, or thus we see, rather than and it came to pass. In 3 Nephi 26:6-9 Mormon comments as follows:
And now there cannot be written in this book even a hundredth part of the things which Jesus did truly teach unto the people;
But behold the plates of Nephi do contain the more part of the things which he taught the people.
And these things have I written, which are a lesser part of the things which he taught the people; and I have written them to the intent that they may be brought again unto this people, from the Gentiles, according to the words which Jesus hath spoken.
And when they shall have received this, which is expedient that they should have first, to try their faith, and if it shall so be that they shall believe these things then shall the greater things be made manifest unto them.
This book refers to Mormon’s abridgement, that we have as the Book of Mormon and plates of Nephi refers to the Large Plates that Mormon is abridging. We don’t know what the document contained that Mormon was abridging, we only have the abridgment. However, the Savior must have informed Nephi of the prayer he uttered when He went a little way off and instructed him to record it in the record that he was keeping. Thus Mormon would have been able to add that information in his abridgement.