Who wrote the scriptures you quoted above?
No, I'm not LDS, I just lived in Salt Lake City for 8 years.
I’m pinging some LDS FReeper to keep this going and expound on other references I missed, since I won’t be online much for the next week or so.
To answer your question, these are revelations given to Joseph Smith and other church leaders, and are part of the Doctrine and Covenants, part of the Church canon which include the Bible and Book of Mormon.
Cheers.