Well, post #30 includes this citation from Joseph Smith's nephew, "prophet" of the church:
...this doctrine of the eternal union of the husband and wife and OF PLURAL MARRIAGE, is one of the most important doctrines ever revealed to man in any age of the world. Without it man would come to a full stop; without it we never could be exalted to associate with and become gods neither could we attain to the power of eternal increase... (Joseph F. Smith, Journal of Discourses, Vol. 21, pp. 9-10)
When shown statements from ‘prophets’; our FR Mormons tend to ignore them.