ISMENE. I'm older than you are. I always think things over, and you don't. You are impulsive. You get a notion in your head and you jump up and do the thing straight off. And if it's silly, well, so much the worse for you. Whereas, I think things out.
ANTIGONE. Sometimes it is better not to think too much. 
ISMENE. I don't agree with you.

This line appears toward the beginning of the play as Ismene, unaware of Antigone’s act of transgression, attempts to convince her sister not to bury their brother, Polynices. The tone of this moment is particularly critical and emphasizes just how different the two sisters are from one another. Ismene advocates for order and reason, even if it requires personal compromise, while Antigone strongly believes in following the instincts she derives from her own moral code. 

ANTIGONE. I'm sallow, and I'm scrawny. Ismene is pink and golden. She's like a fruit.

In addition to being foils in terms of personality and worldview, Antigone and Ismene are also foils in terms of their physical appearances. This line, which Antigone delivers as she talks to Haemon about their relationship, suggests that Ismene embodies a more traditional type of femininity while Antigone is unconventionally beautiful. As a result of this difference, Antigone feels insecure in her relationship with Haemon, and she struggles to picture herself living the life of happiness that her idealized sister will undoubtedly attain.

ANTIGONE. You chose life and I chose death. Now stop blubbering. You had your chance to come with me in the black night, creeping on your hands and knees. You had your chance to claw up the earth with your nails, as I did; to get yourself caught like a thief, as I did. And you refused it.

When Ismene barges in on Antigone’s fight with Creon, she proclaims that she has had a change of heart and wants to join her sister in death. Antigone, however, refuses to let Ismene take a part in her act of rebellion, and this attitude serves as a call back to the tension between them earlier in the play. Despite the fact that they never truly reconcile their differences, Ismene’s newfound willingness to bury her brother highlights the inspiring nature of Antigone’s refusal to compromise her beliefs.