Answer:
She feels as though Divine Law is more important than Mortal Law. She does not fear the kings rule because the defy the Gods rules. Because he is also her brother, she feels that her brother deserves a true burial, as the Gods would want. Ismene does acknowledge this, however she is more afraid of the Kings punishment.
Explanation:
I do not have the text with me at the moment, I'm sorry. However if you find the section at the very beginning, the two sisters are arguing over Antigone wanting to bury Polyneices. Their dialogue is evidence enough.
