As part of Jesus’s self-introduction, he reaffirms his role. “Bitter cup” appears only once before in the Book of Mormon, and then in a completely different context. Alma tells Corianton: “But behold, an awful death cometh upon the wicked; for they die as to things pertaining to things of righteousness; for they are unclean, and no unclean thing can inherit the kingdom of God; but they are cast out, and consigned to partake of the fruits of their labors or their works, which have been evil; and they drink the dregs of a bitter cup” (Alma 40:26).
The experience of the wicked with the bitter cup is certainly not the same as for Jesus. It is possible, however, that the bitter cup expresses the consequences of sin which Jesus suffered for us but for which the wicked would suffer themselves. In either case, the experience is an agonizing process.
The allusion to “bitter cup” comes from a combination of scripture and common phrasing. From scripture we have:
And he went a little further, and fell on his face, and prayed, saying, O my Father, if it be possible, let this cup pass from me: nevertheless not as I will, but as thou wilt.
And he cometh unto the disciples, and findeth them asleep, and saith unto Peter, What, could ye not watch with me one hour?
Watch and pray, that ye enter not into temptation: the spirit indeed is willing, but the flesh is weak.
He went away again the second time, and prayed, saying, O my Father, if this cup may not pass away from me, except I drink it, thy will be done. (Matt. 26:39–42)
While the cup image appears in this passage, it is not “bitter.” Nevertheless, “bitter cup” appears to have entered into common use, possibly from Joseph Smith’s experience.
Reference: Jesus also declares himself as the “light of the world.” He had made the same declaration in the New Testament:
As long as I am in the world, I am the light of the world. (John 9:5)
Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life. (John 8:12)
Pairing the “light and life of the world” is unique to the Book of Mormon. (See also Mosiah 16:9; Alma 38:9.) However, the concept that Jesus was the life of the world is certainly biblical. Jesus as both “life” and “light” are texts unique to the Gospel of John:
I am come a light into the world, that whosoever believeth on me should not abide in darkness. (John 12:46)
For the bread of God is he which cometh down from heaven, and giveth life unto the world. (John 6:33)