Jesus prayed for the leaders and for all those who believe in him through their teaching, that they might be one, that they might be united—the same salient doctrine he taught his disciples in the Old World, as recorded in his great intercessory prayer (John 17).
The concept of oneness is both important and urgent in the gospel of Jesus Christ. It is the vital message inherent in the English word atonement (at-one-ment), the idea of becoming one.
Note how the Lord uses various parts of the Father’s crowning creation, the physical body for each of his children, to illustrate the desirability of one-ness: the children of God lived “with one eye … having their hearts knit together in unity” (Mosiah 18:21; emphasis added); “them that believed were of one heart and of one soul” (Acts 4:32; emphasis added); “his people ZION … were of one heart and one mind” (Moses 7:18; emphasis added); “we, being many, are one body in Christ” (Romans 12:5; emphasis added); “stand fast in one spirit, with one mind” (Philippians 1:27; emphasis added). One eye, one mind, one heart, one body, one spirit, and one soul. Every member of the body is needed; all members must unite together in order for the body of Christ to function perfectly.
To establish Zion, then, we must become of one heart and one mind. God does not seem to be celebrating diversity but unity. That may not be too popular a notion in the world, but the Godhead is encouraging us to become like they are—to feel and to think and to act as they do.
“I and my Father are one,” Jesus proclaimed (John 10:30; see also D&C 50:43; 93:3). So much alike are they that if we know one, we know the others. The Father, the Son, and the Holy Ghost are one God (2 Nephi 31:21; Alma 11:44; 3 Nephi 11:36; D&C 20:28). Of us the Savior said, “They may become the sons of God, even one in me as I am one in the Father, as the Father is one in me, that we may be one” (D&C 35:2; emphasis added).
Is all this “three are one” merely theological doubletalk, or is there something profoundly significant and sacred in this doctrine?
Surely the three Gods are teaching us mortals the fundamental and indispensable principle that will lead us to become as they are. In that great intercessory prayer, our Advocate with the Father pleaded with him: “Holy Father, keep … those whom thou hast given me, that they may be one, as we are …
“That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: …
“And the glory which thou gavest me I have given them; that they may be one, even as we are one:
“I in them, and thou in me, that they may be made perfect in one” (John 17:11, 21–23; emphasis added).
There is the foundational reason for us to be united, as one: to become perfect. “I say unto you, be one; and if ye are not one ye are not mine” (D&C 38:27; emphasis added). In all the above passages we see the basic meaning of that otherwise abstract word atonement; the great sacrificial offering of the Lamb is meant to help us become as one—one with him and the Father and one with each other.