Whoever this narrator is, he really likes Billy Budd. A lot. One of the ways that you can tell is that he is constantly comparing Billy Budd to religious figures. The comparisons mainly fall into two different categories: those linking Billy to the Biblical Adam before the "Fall of Man," and those comparing Billy to Jesus Christ. We'll deal with the Adam comparisons in "The Noble Savage" section (see below). Here, we're mainly concerned with what it means for the narrator to treat Billy as an 18th-century Christ figure.
Let's focus in on Billy's execution scene. Billy's last words are "God Bless Captain Vere!" (25.2). The words aren't too far off from Christ's own cry of forgiveness in Luke 23:24 – "Father, forgive them for they know not what they do." In a way, though, Billy's forgiveness is even more remarkable. Forgiveness, of course, implies that there's something to forgive, that there is something that the forgiver could begrudge the one who he is forgiving.
With Billy, though, he doesn't even seem to hold anything against Captain Vere after Vere condemned him to death. It's almost like he doesn't understand that he has reason to be angry with Captain Vere or to resent him. After all, he isn't actually forgiving Vere. It's more like he's affirming Vere's decision to execute him and hoping that God will give Vere strength since Billy knows that he is going to be wracked by guilt.
In this way, Billy appears more remarkable (or maybe less human) than Christ does in the Bible. For Billy there is not a single moment where his faith wavers. The moment in the Garden of Gethsemane where Christ says, "My God, my God, why have you forsaken me?" (Matthew 27:46) simply does not exist for Billy. People often have trouble relating to Christ because he is so good. The whole point, of course, is that Christ is part divine and part human, meaning that he is capable of human weakness and sin. In a way, though, Billy is even harder to relate to.
What does this mean? Is the narrator trying to replace Christ with Billy?
Actually, this probably has a lot more to do with the narrator himself than it does with either Billy or Christ. Consider how the narrator describes the moment when Billy is hanged:
At the same moment it chanced that the vapory fleece hanging low in the East was shot through with a soft glory as of the fleece of the Lamb of God seen in mystical vision, and simultaneously therewith, watched by the wedged mass of upturned faces, Billy ascended; and, ascending, took the full rose of dawn. (25.5)
As we point out in "Writing Style," the narrator seriously romanticizes Billy's execution. After all, who can say what the light of the "Lamb of God" looks like? Is this something that the narrator actually saw or something that he is reading into what he saw?
In the final chapter of the book, the narrator notes how the sailors kept track of the spar (big pole of the main mast) where Billy died. As he says, "To them a chip of it was as a piece of the Cross" (30.1). The narrator, who clearly considers himself superior to the sailors, seems to portray their worship of Billy as excessive and sentimental. Yet, if you take a minute and read back over the passages that compare Billy to Christ, you'll quickly realize that the narrator himself does this to an even greater degree.
By making Billy even more Christ-like than Christ, the narrator idealizes him to the point that it's hard to imagine Billy as a real human figure, as someone with whom it is possible to empathize. One of the great ironies of Billy Budd is that, in seeking to exonerate the main character, the narrator actually makes him disappear by removing him from the realm of human beings that it is possible for us to imagine.