Where we are
Moroni 5 is the second of the two sacrament prayers, the prayer over the wine, and it completes the ordinance that Moroni 4 began. Where the bread is taken in remembrance of the body of thy Son, the wine is taken in remembrance of the blood of thy Son, which was shed for them (v. 2). Together the two prayers hold the whole atonement — the body broken and the blood shed — and the two emblems renew, week by week, the covenant of discipleship. The chapter is two verses, but it is the necessary other half of the sacrament: the blood remembered beside the body, the cup beside the bread, the complete memorial of Christ's offering. Moroni preserves it, as he preserved the prayer on the bread, so that the future church might renew the covenant in the same words the Nephite church used and the risen Lord commanded.
The chapter's two verses give the act and the prayer: they took the cup (v. 1) and prayed that God would bless and sanctify this wine to the souls of all those who drink of it, that they may do it in remembrance of the blood of thy Son, which was shed for them; that they may witness unto thee... that they do always remember him, that they may have his Spirit to be with them (v. 2).
The verse that carries the chapter is verse 2, the prayer itself — the remembrance of the blood... which was shed for them, the witness that they do always remember him, and the promise that they may have his Spirit to be with them. The chapter exists to complete the sacrament, preserving the prayer over the wine so that the blood of Christ is remembered alongside his body, and the covenant of always remembering him is renewed in full.
The prayer on the wine (verses 1–2)
O God, the Eternal Father, we ask thee, in the name of thy Son, Jesus Christ, to bless and sanctify this wine to the souls of all those who drink of it, that they may do it in remembrance of the blood of thy Son, which was shed for them. — Moroni 5:2
The prayer on the wine mirrors the prayer on the bread, with one essential difference: it remembers the blood of thy Son, which was shed for them. The phrase shed for them makes the remembrance personal and atoning — the blood was not merely shed but shed for them, for the very souls now drinking the cup. This is the wine's particular witness: the body was given, and the blood was shed for us. The two emblems together hold the two aspects of the atonement — the broken body and the shed blood — and the wine focuses the remembrance on the cost, the blood poured out for our sins. The risen Lord gave the cup among the Nephites (3 Nephi 18:8–11) as he had at Jerusalem, this is my blood of the new testament, which is shed for many (Mark 14:24). The prayer asks God to bless and sanctify the wine to the souls of those who drink — again the soul, not the body, for the sacrament feeds the spirit. Moroni preserves the prayer so that the blood of Christ, shed for us, would be remembered in the cup, week after week, alongside the body remembered in the bread.
...that they may witness unto thee, O God, the Eternal Father, that they do always remember him, that they may have his Spirit to be with them. Amen. — Moroni 5:2
The prayer on the wine is briefer than the prayer on the bread, and the difference is instructive. The bread-prayer named the full threefold covenant — take his name, always remember him, keep his commandments. The wine-prayer names only one of the three: that they do always remember him. The covenant has already been made over the bread; the wine seals it with the single, central promise — always remember him. This is the heart of the whole sacrament, repeated in both prayers (the bread asks willingness to always remember, the wine witnesses that they do always remember). The repetition is deliberate: remembrance is the soul of the ordinance, and it is named in both emblems. And the promise is the same — that they may have his Spirit to be with them. The two prayers end identically on the Spirit, because the gift of the sacrament is the same in both: the constant companionship of the Holy Ghost, granted to those who remember Christ. The wine completes what the bread began — the blood remembered beside the body, the covenant of remembrance sealed, the Spirit promised. Moroni preserves both halves so that the future church would have the whole sacrament, the complete memorial of the body and the blood, and renew the covenant of always remembering in full.
How the chapter is built
Moroni 5 is built as the completing half of a pair, and it can only be fully understood beside Moroni 4. The two chapters are deliberately parallel — same address (O God, the Eternal Father), same authority (in the name of thy Son), same request (bless and sanctify... to the souls), same promise (that they may have his Spirit) — with the one essential variation: bread/body, wine/blood. The architecture is liturgical symmetry, the two prayers built on the same frame so that the body and the blood are remembered in matching words. The brevity of the wine-prayer relative to the bread-prayer is itself structural: the full covenant is stated once, over the bread, and the wine seals it with the single central promise of always remember, so the pair together gives the whole covenant without needless repetition.
The chapter is also built to make remembrance the soul of the sacrament by repeating it across both emblems. The bread asks willingness to always remember him; the wine witnesses that they do always remember him. The architecture places always remember in both prayers, and only always remember in the wine, so that the reader sees what the ordinance is finally about. Of the three covenants named over the bread, the one repeated over the wine is remembrance — because remembrance is the heart, the thing the body and the blood both call us to, the antidote to the forgetting that destroyed the peoples of the Book of Mormon. The structure of the pair teaches that the sacrament is, above all, the ordinance of remembering Christ — his body and his blood — so that the Spirit may always be with us.