16 Behold, I send you forth as sheep in the midst of wolves: be ye therefore wise as serpents, and harmless as doves. (Matthew 10:16, King James Version)

The Biblical allusion to Mathew 10:16 occurs in Chapter 2: New man aboard the Indomitable. Melville is in the process of building Billy's initial characterization, so the allusion is meant to do what all allusions do. Allusions give a great deal of information in a very condensed space by drawing upon culturally shared knowledge of significant import that paints a vivid impression with few words. What this means is that Melville tells readers a great deal about Billy with very few words by associating him with something that readers could be expected to deeply understand. This of course may not be true of todays Western readers of Billy Budd because the culture of nearly universal religious training and participation ended quite some time ago.

Starting, therefore, with the allusion, Matthew 10:16 means that since Jesus is sending his disciples out into a social environment with people he compares to wolves, he advises them to be as wise and crafty and knowledgeable as serpents (in Genesis, the Serpent used knowledge and guile to trick Adam and Eve out of the Garden of Eden) yet, as his representatives, as gentle and harmless and lovely as doves.

The narrator has just described Billy as the English version of the Greek god Hercules, born of "a mother eminently favored by Love and the Graces," prior to his formal act of being "mustered" into the service.

he showed in face that humane look of reposeful good nature which the Greek sculptor in some instances gave to his heroic strong man, Hercules.

The officer in charge, "a small brisk little gentleman," asks Billy the standard questions. Billy responds by revealing his unknown background. The narrator goes on to describe Billy's inner character by describing him as having little similarity to the "wisdom of the serpent" and equally little similarity to "a dove." The narrator goes on to say that Billy does however have the native intelligence of a well born human being, a "sound human creature."

What this means is that, while illiterate and lacking in educated reasoning ability and mental "faculty" or schooled "wisdom," Billy is nonetheless intelligent and talented ("he could sing") in accord with what he is naturally endowed with. By the same token, Billy is no gentle "dove" who is unable to get along on his own. In sum: Billy is not schooled nor wise nor overly gentle, but he is able and intelligent and talented and a master of his own piece of innocent world where he knew "little more of the land than as a beach."

By his original constitution aided by the cooperating influences of his lot, Billy in many respects was little more than a sort of upright barbarian, much such perhaps as Adam presumably might have been ere the urbane Serpent wriggled himself into his company.