Final answer:
Antigone is motivated by her sense of familial duty and higher moral principles, while the guard is motivated by fear and self-interest.
Step-by-step explanation:
Antigone's motivation for returning to her brother's body is driven by her familial duty and her belief in honoring divine laws over human ordinances. She argues that her actions are justified by her conscience and she is willing to face the consequences, even if it means death.
On the other hand, the guard's motivation for returning to her brother's body is driven by fear and self-preservation. In his account to Creon, the guard explains that he initially fled from the burial site, but eventually decided to return and fulfill his duty out of fear of the king's wrath.
In summary, Antigone is motivated by her sense of familial duty and higher moral principles, while the guard is motivated by fear and self-interest.