21 I say unto you, ye will know at that day that ye cannot be saved; for there can no man be saved except his garments are washed white; yea, his garments must be purified until they are cleansed from all stain, through the blood of him of whom it has been spoken by our fathers, who should come to redeem his people from their sins.
Sure enough, this same teaching was revealed to Nephi, which we find in 1 Nephi 12:
10 And these twelve ministers whom thou beholdest shall judge thy seed. And, behold, they are righteous forever; for because of their faith in the Lamb of God their garments are made white in his blood.
11 And the angel said unto me: Look! And I looked, and beheld three generations pass away in righteousness; and their garments were white even like unto the Lamb of God. And the angel said unto me: These are made white in the blood of the Lamb, because of their faith in him.
This same concept is referenced again by Moroni, writing to those who do not believe in Christ. From Mormon 9:
6 O then ye unbelieving, turn ye unto the Lord; cry mightily unto the Father in the name of Jesus, that perhaps ye may be found spotless, pure, fair, and white, having been cleansed by the blood of the Lamb, at that great and last day.
Much has been written about the extensive description of the righteous peoples of the Book of Mormon being "fair" and "white," but I believe these descriptors refer to the spiritual effects of keeping covenants. For the most part, the Nephites were the covenant-keepers, whereas the Lamanites were those who had rejected the covenant.
Over a series of posts, I'm going to review how the Book of Mormon uses terms like light/white/fair/delightsome to refer to making and keeping covenants.