For example, see Alma 8:1
1 And now it came to pass that Alma returned from the land of Gideon, after having taught the people of Gideon many things which cannot be written, having established the order of the church, according as he had before done in the land of Zarahemla, yea, he returned to his own house at Zarahemla to rest himself from the labors which he had performed.
In a similar manner, after the endowment was first administered in this dispensation by Joseph Smith in 1842, Heber C Kimball wrote to fellow Apostle Parley P. Pratt (who had not been in attendance):
"Some precious things through the Prophet on the priesthood that would cause your soul to rejoice...I cannot give them to you on paper for they are not to be written."
