Placing opposite ideas or words side by side, so that one illuminates the other through contrast.
In Madame Bovary
She wanted a boy [...] A man, at least, is free, can explore all passions and all lands, overcome obstacles, taste the most distant joys. But a woman is continually hindered in everything.
The passage sets the man, who "is free," against the woman, "continually hindered in everything." The direct contrast between freedom and hindrance sums up what Emma feels as the injustice of having been born a woman, and gives force to the final sentence.
Part II, Chapter 3, the narrator
Ah!, but there are two [...] the petty, the conventional, that of men, which varies constantly and shouts so loudly that it stirs upon the ground, down to earth [...] But the other, the eternal one, that encircles everything and stands above everything, like the landscape that surrounds us and the sky that lights us.
You are taking advantage of my distress with impunity! I am to be pitied, but not sold!
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