This is the reason for this doctrine. It will allow those who accept and follow it to endure against all enemies. It will allow them to prevail.
Even the "gates of hell shall not prevail against them." Meaning that death and hell can have no claim upon them. They will not be taken captive either in this world (Alma 12: 11) or when they leave this world (Alma 40: 13.)
When we consider the Father is to bear record of the Son, and the Son bears record of the Father, and the Holy Ghost bears record of the Father and Son, then we realize this doctrine of Christ is designed to put us in contact with all three members of the Godhead. We are to join them. We are to be one with them.
There is no separating us from God when we have the record of each given to us.
It is interesting that the "rock" upon which we build is the Father, Son and Holy Ghost. There is abundant evidence of other "gods" and of "goddesses." It is beyond dispute that the "image of God" includes both "male and female." (Gen. 1: 27; Moses 2: 27; Abraham 4: 27.) It is inescapable, therefore, that the God we worship includes a Father and a Mother. However, we are only to seek after the Father, Son and Holy Ghost as the "rock" upon which our salvation is to be built.
Oddly enough, mankind prefers a female deity over a male deity. Catholicism has reconciled this preference by the doctrine of Immaculate Conception and the cultic veneration of Mary. Pope John Paul II was an ardent believer in the Cult of Mary and made no secret of that veneration. It is almost beyond dispute that Mary's status is preferred over Christ's in the lives of the common Catholic.
In the Old Testament, the goddess Ashtoreth, (in her various iterations) was a leading figure in apostasies of ancient Israel. She was the female consort to Baal (who also had various spellings). The Egyptian counterpart being Hathor, whose image appears in figure 5 of Facsimile No. 2 in the Book of Abraham. The representation there being Egyptian, that is, emerging through the great cycle of life, afterlife and resurrection coming through the womb. An understanding of which Hugh Nibley was setting forth in One Eternal Round. This work was reduced in volume by half before publication. This resulted in problems with the published text. That, however, is another subject not relevant here.
Notwithstanding man's preference for the female god, for salvation we must anchor ourselves to the Father, Son and Holy Ghost. They are the "rock" upon which we must build to avoid the gates of hell, despite our knowledge of heaven, salvation and the necessary unity of the sexes before salvation is obtained. (1 Cor. 11: 11.) It is through the union of the sexes that mortals imitate immortality, for all of us will die. Yet if joined together we will continue through the seed forever, as the gods. (D&C 132: 20-22.)
There is also the continuing trouble about polygamy which so often afflicted the discussions on this blog before comments were discontinued. Those who preach on the subject often speak out of the coarseness of ambition and insecurity (for those always go together), and without understanding how a marriage must work to warrant preservation beyond this life.
Ask yourself what kind of a relationship would be godlike? What association between a man and a woman would be something the heavens would want to preserve and continue? Is an ambitious man who looks upon a woman as someone to rule over worthy of heavenly preservation? Is such a man worthy of one wife, let alone several?
Wouldn't you expect the relationship between a man and woman worthy of eternal preservation to evidence such things as equality, respect, kindness, joyful and voluntary interchange of thoughts, and to be grounded in love? Wouldn't you expect such a marriage to be part of heaven, though the parties live as mortals on the earth? Why would you expect a form of marriage, having as its chief output, unhappy but frequently pregnant women, having an absentee husband to be godlike?
Have you read the tenth parable? If you have and still think you need a "brood" of women to become godlike, then you haven't understood the tenth parable.
Foolishness never was enlightenment. Ambition is unbecoming in a candidate for exaltation. We will keep going into Christ's sermons to the Nephites and, as we do, you will find He emphasizes how to become like Him through service and abasing yourself. By sacrifice and devotion to the best interests of others. Not by compulsion, dominion and ruling over others.
If you want to prevail against the gates of hell, then Christ's simple doctrines need to become yours. They need to be how you live and what you do. They are the only rock upon which you can build and have something which will endure the buffetings of hell itself.
If a man hasn't made a single woman happy, why would he be trusted to have more wives? Why would he want them? What does such a man think the purpose of marriage to be? Gratification? Industrial baby-production? What's the reason? If happiness is the end of our design by God, then wouldn't you need to find someone who can live in peace and happiness with another person as their husband as the first step? If that is true, then why isn't that challenge enough in a marriage between one man and one woman? Until that has been conquered, why should misery be multiplied by adding additional spouses into a failed interpersonal relationship?
Too many people are advocating too many alternatives which distract from the simplicity of what is really needed. There aren't enough marriages worthy of preservation. Make yours one of them. That is a very good work and challenge enough for all of us at present.