Mormon considers himself in a position to dictate to his son what ought to happen in the church. This presumes a position of authority in the church and we learned in 3 Nephi 5:13 that “I am a disciple of Jesus Christ, the Son of God. I have been called of him to declare his word among his people.” Mormon is therefore an apostle, and with the calling of Moroni to the ministry (presumably as an elder, or apostle) then Mormon not only has priority of time and experience, but seniority of position. Mormon is therefore may write to his son not only as a concerned father, but as an apostle who is distant from the problem (and otherwise preoccupied with war) who expects another apostle to guide the church through a doctrinal issue.