While Meg focuses on her unhappiness at her father's absence and her problems at school, Calvin must remind her how lucky she is to have a family like hers in which there is so much love. Meg's love for her father enables to her to undertake the journey with the Mrs. W's in the first place, and Meg's love for Charles Wallace is the weapon with which she is able to save Charles Wallace and defeat IT. Love is the only thing she has that IT doesn't have—love is something that can only exist between different people, while IT destroys all difference. While Meg may think love a paltry thing at the beginning of the book, by the end she realizes she could possess nothing more empowering or valuable.
The Value of Love ThemeTracker
The Value of Love Quotes in A Wrinkle in Time
"Lead on, moron," Calvin cried gaily. "I've never even seen your house, and I have the funniest feeling that for the first time in my life I'm going home!"
Charles. Charles, I love you. My baby brother who always takes care of me. Come back to me, Charles Wallace, come away from IT, come back, come home. I love you, Charles. Oh, Charles Wallace, I love you.