Mormons actually use the verses you quoted from Jacob to support polygamy.
“30 For if I will, saith the Lord of Hosts, raise up seed unto me, I will command my people; otherwise they shall hearken unto these things” is interpreted to mean:
“Don’t do it unless God says it’s ok.”
I know.
But the FR Mormons haven't in a REALLY long time, since when they are shown in CONTEXT...
There goes driving cars, flying on planes, tweeting and twittering all over the place...
...eating flesh of animals in warm weather..
Oh...
Wait...