As part of Jesus’ self-introduction he reaffirms his role. The “bitter cup” imagery appears only once before in the Book of Mormon in a completely different context. Alma uses the phrase when speaking to his son:
Alma 40:26
26 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.
The imagery is that of an unpleasant experience. Certainly the two “drinkings” of the “bitter cup” are not to be equated, as 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 did suffer for us, and in that way the terms would be similar.
Life and Light of the World: Jesus self-declares himself the “light of the world” in the New Testament:
John 9:5
5 As long as I am in the world, I am the light of the world.
John 8:12
12 ¶ 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.
The particular pairing of “light and life of the world” is unique to the Book of Mormon, and is found in Mosiah 16:9 and Alma 38:9 as well as the current verse. While this pairing is unique to the Book of Mormon, the conception that Jesus was the life of the world is certainly Biblical. It is interesting that each of these separate concepts, that Jesus is the light of the world and that Jesus is the life of the world, are uniquely Johnanine texts.
John 12:46
46 I am come a light into the world, that whosoever believeth on me should not abide in darkness.
John 6:33
33 For the bread of God is he which cometh down from heaven, and giveth life unto the world.
The Bitter Cup: The scriptural reference for this phrase comes from a combination of scripture and common phrasing. From scripture we have:
Matthew 26:39-42
39 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.
40 And he cometh unto the disciples, and findeth them asleep, and saith unto Peter, What, could ye not watch with me one hour?
41 Watch and pray, that ye enter not into temptation: the spirit indeed is willing, but the flesh is weak.
42 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.
The obvious difference is that Matthew has a cup, but not a “bitter” cup. Nevertheless, this phrase, “bitter cup” appears to have entered into typical phraseology and common use. We may see that particular combination coming from Joseph Smith’s experience.
The rest of the passage is unique to the Book of Mormon.