How does Whitman use allusion in the poem, O Captain! My Captain!?

Upon first revealing that his “Captain lies, / Fallen cold and dead” at the end of the first stanza, the speaker seems initially reluctant to acknowledge the permanence of his beloved Captain’s passing (7-8). Immediately afterwards, in the next stanza, the speaker calls out excitedly and directly to his Captain, as emphasized by the exclamation points, “O Captain! my Captain!” and almost seems to command him to “rise up and hear the bells” from “the people all exulting” (3, 9). He underscores his urgency with the repeated request at the beginning of the next line for his Captain to “Rise up” (10). The idea that the Captain may rise up again, that that his death is not permanent, suggests several Biblical allusions to Jesus raising Lazarus from death and even the resurrection of Jesus himself. With these allusions, the speaker seems to cast his Captain a pseudo-religious miraculous figure who, in response to the expectations of those on the shore, has the capacity to defy the reality and finality of death. To the speaker at the end of the second stanza, “It is some dream on that on the deck, / You’ve fallen cold and dead” (15-16). By referring to the Captain's death as a "dream," the speaker showcases his own denial over the humanity and vulnerability of the Captain.