3 Nephi - Chapter 16

The Savior admonishes the people to write the experiences they are having in His presence.  Elder Richard G. Scott tells us:

This experience also created an environment where strong impressions flowed. I wrote them down. One paragraph began, "Testify to instruct, edify, and lead others to full obedience, not to demonstrate anything of self. All who are puffed up shall be cut off." Another signaled, "You are nothing in and of yourself, Richard." That was followed with some specific counsel on how to be a better servant. The impressions became so personal that I felt it inappropriate to record them in the midst of a Sunday School class. I sought a more private location. There I continued to write the feelings that flooded into my mind and heart as accurately and as faithfully as possible. After each powerful impression was recorded, I meditated upon it and pondered the feelings I had received to determine if I had accurately interpreted them. Then I studied their meaning and application in my own personal life.

Richard G. Scott was a member of the Quorum of the Twelve Apostles of
The Church of Jesus Christ of Latter-day Saints when this devotional
address was given at Brigham Young University on 17 August 1993.

That is good counsel for us and our spiritual experiences.  Certainly it served that purpose for those ancient Americans as well.

Additionally, the Lord prophecies that the words they record will one day be of great service in carrying the restored gospel to all the world, most especially to scattered Israel.  Mormon tells us that the piles of records in his possession were enormous.  Had you lived then might your writing, your journal, have been included in that pile?  Might the words and feelings you recorded about the inspiration you received have been part of the story and doctrine Mormon gleaned for the great abridgment of those records that became The Book of Mormon?

My own grandmother kept a journal.  Reading it has helped to gather me out of the world and draw me to Zion.  How I appreciate those who expressed gratitude for the revelation they received by writing it down where I might, reading, be edified and drawn to the Lord.