The envy that Claggart feels towards Billy is emphasised in Chapter 13 through the focus on the way in which Claggart's envy of Billy's heroic character and handsome features is not just a simple envy as experessed in situations such as Saul's envy of the youthful and handsome David. The text in this chapter insists that Claggart's envy of Billy "struck deeper" than this, and that Claggart's envy of Billy is somehow characterised by Claggart's identification of Billy as a true innocent, a character who has never experienced the "reactionary bite of that serpent," as the following quote explores:
If askance he eyed the good looks, cheery health and frank enjoyment of young life in Billy Budd, it was because these went along with a nature that, as Claggart magnetically felt, had in its simplicity never willed malice or experienced the reactionary bite of that serpent. To him, the spirit lodged within Billy, and looking out from his welkin eyes as from windows, that ineffability it was which made the dimple in his dyed cheek, suppled his joints, and dancing in his yellow curls made him preeminently the Handsome Sailor.
It is enough for Claggart, as an evil character, to see Billy Budd as a representation of innocence and goodness, as partly expressed through his physical beauty, and this is shown to be the source of his envy. Claggart in this chapter is defined as a character who has "elemental evil" within him, who can "apprehend the good" but at the same time is "powerless to be it." His envy therefore stems from Billy Budd representing something that Claggart clearly feels attracted to but can never be because of his evil nature. This fits into one of the novel's larger thematic concerns which is that of the nature of evil, and whether characters are, like Claggart is presented, born evil without any hope of redemption, or whether being evil is a condition rather than a state. Claggart is presented in this novel as something of a Satan figure who serpent-like abuses and manipulates Billy's innocence for his own devious purposes.