In Alma 46:26 it says, "Now behold, this was the language of Jacob." According to Hugh Nibley, this means that they had the written document [of this story about the garment remnant]; it was among the brass plates probably. . . . Moroni says, "Let us remember the words of Jacob" when he starts out (see Alma 46:24). Then he ends up by saying, "Now behold, this was the language of Jacob." They had the records. [Hugh W. Nibley, Teachings of the Book of Mormon, Semester 3, p. 63]