In your view of Mormonism, does Abraham and Sarah represent being the father and mother of humanity, or something like that? I found a Mormon website called Mormon Interpreter, and there’s an interesting article there by an Andrew Smith, regarding Abraham, Sarah, and Hagar. The article seems to allocate the Blessed Virgin Mary (not the term they use for her) to the same sort of role as that of Hagar. Abraham and Sarah are like a new Adam and Eve (the first parents of humanity) and Abraham and Sarah are sort of like the second parents. Hagar’s son goes on the become the patriarch of the Ishmaelites (which seems to somehow seems important to Mormons), which seems to have some sort of correlation to the Blessed Virgin Mary (an infallible human like Hagar, according to the Mormon author), who gives birth to Jesus.
It’s all rather bizarre, and has no relation to the New Testament or Christianity as we Catholics (or Protestants) know it, but I’m just trying to figure out how Mormon’s think, and why there’s this focus on Hagar and Abraham. I have to wonder if it has more importance or significance than just condoning plural marriage, though maybe this explanation on the website that isn’t all that common among Mormons. But it might explain why they think that the BVM isn’t very special, I think.