Section 2 of the Doctrine and Covenants is entirely composed of the a selection from the teachings of the Angel Moroni to Joseph Smith, Jr.  It is indicative of a common trend among such visits, being that they often quote scripture to us.  It has been said, and I believe it to be true, that if we want to know what the Lord, or his angels, would tell us today, we can find most of it in the scriptures already.