How we cite our quotes:
He fought a rising hysteria that was not merely anxiety to free his aching feet; his very life depended on the release of the knots. Suddenly, without raising his eyelids, he began to cry. (1919.17)
Shadrack's suffering is both physical and mental, and it creates a framework for the rest of the novel. His feet are in pain from having to walk so far, but the more significant suffering is the feeling of being tied up in knots, a feeling several other characters share.
So soon. So soon. She hadn't even begun the trip back. Back to her grandmother's house in the city where the red shutters glow, and already she had been called "gal." All the old vulnerabilities, all the old fears of being somehow flawed gathered in her stomach and made her hands tremble. (1920.16)
Racism has created deeply ingrained feelings of inferiority in Hannah. The conductor calls her "gal" to diminish her, and this recalls for her the suffering she felt before moving to the Bottom.
Eva squatted there wondering . . . what she was doing down on her haunches with her beloved baby boy warmed by her body in the almost total darkness, her shins and teeth freezing, her nostril assailed. She shook her head as though to juggle her brains around, then said aloud, "uh uh. Nooo." (1921.6)
This is the suffering of a woman abandoned by her husband with no way to support her children. Eva is at the height of her suffering here: cold and engulfed in darkness as she tries to protect Plum. This is the last straw for her, and this extreme suffering causes her to vow to make a change.