We know that the Atonement is infinite, but what does that mean?

We first find this idea that the Atonement must be infinite in 2 Nephi 9:7, where Jacob explains about the Atonement and the resurrection. In this verse, he does not seem to use “infinite” to mean “of endless duration.” He says, “Wherefore, it must needs be an infinite atonement – save it should be an infinite atonement this corruption could not put on incorruption.” What does duration have to do with changing corrupt mortal bodies into incorrupt immortal bodies? Nothing that I can think of.

Next we move to 2 Nephi 25:16. In this verse, Nephi appears to use the word “infinite” to mean that the Atonement is limitless in scope: the Jews will be scattered “until they shall be persuaded to believe in Christ, the Son of God, and the atonement, which is infinite for all mankind.”

In a sermon that may be unsurpassed in explaining the Atonement, Amulek teaches that “it is expedient that there should be a great and last sacrifice; yea, not a sacrifice of man, neither of beast, neither of any manner of fowl; for it shall not be a human sacrifice; but it must be an infinite and eternal sacrifice.” Alma 34:10. That seems to be pretty clear – the “great and last sacrifice,” the Atonement of Jesus Christ, must be “infinite and eternal” because an animal sacrifice or human sacrifice will not suffice. He explains in the next verses that, under Nephite law, a man cannot sacrifice his own blood to atone for the sins of another. Instead, the law requires the life of the murderer. Because of this, nothing short of “an infinite atonement . . . will suffice for the sins of the world.” Alma 34:12. Finally, he explains that the law all points to the Atonement and the One who performs it: “and that great and last sacrifice will be the Son of God, yea, infinite and eternal.” Alma 34:14. What is infinite and eternal? The sacrifice. What is the sacrifice? Not an act, but a being – the Son of God, who is infinite and eternal.

I think that Amulek is saying that the difference between animal or even human sacrifice is not a difference in quantity, but quality. The sacrifice must be of a God Himself, not just a lot of other beings.

In other words, to say that the atonement is infinite and eternal is more than just saying that its effects are of infinite duration and applicability. “Infinite and eternal” also refer to the qualities and characteristics of the Atonement. And those are the qualities and characteristics of God. Modern revelation tells us that “there is a God in heaven, who is infinite and eternal”; “Which Father, Son, and Holy Ghost are one God, infinite and eternal, without end. Amen.” D&C 20:17, 28. In my search of the scriptures, I have found the phrase “infinite and eternal” only in the scriptures I have quoted here – the phrase is used to describe the Atonement and God.

This idea, that “infinite and eternal” describes more than temporal and spatial coverage, is also supported by the definition that the Lord Himself gave of the word “eternal” in modern revelation. In D&C 19:6-12, He explains that “endless” and “eternal” punishment does not mean that there shall be no end to the punishment, but that it is God’s punishment – thus equating “eternal” with “God.”