The third chapter of Nathaniel Hawthorne's The Scarlet Letter focuses on the punishment of Hester Prynne, her refusal to reveal the name of her lover, and the arrival of her husband in disguise. Your chosen quotations should refer to those major themes and events.
When Hester catches sight of her husband in the crowd, she notices that "one of this man's shoulders rose higher than the other." When she sees this and looks at his face, she presses "her infant to her bosom with so convulsive a force that the poor babe uttered another cry of pain." Hester never expects to see her husband standing there, yet she knows him at once, even in his Indian clothing. This shows Hester's powers of observation and quick mind. Further, the only indication of emotion she shows is clutching the child. This is an automatic reaction, but it can also symbolize her fear that someone might try to take her child from her.
When Hester's husband sees her, "A writhing horror twisted itself across his features, like a snake gliding swiftly over them, and making one little pause, with all its wreathed intervolutions in open sight." He then controls himself. This is an interesting, vivid metaphor that reveals the emotional state of the man as he realizes that his own wife is standing before the crowd in shame.
Hester's husband asks a bystander what Hester's offense is, and the man explains, also noting that she refuses to name the father of the child. "Peradventure the guilty one stands looking on at this sad spectacle, unknown of man, and forgetting that God sees him," the man says. This quotation captures the irony inherent in the story. The father of Hester's baby is indeed looking on, but he certainly knows that God sees him.
In response to the bystander's explanation of Hester's punishment, her husband-in-disguise wishes that her partner in adultery was standing next to her on that scaffold. Then he exclaims, "But he will be known—he will be known!—he will be known!" Hester's husband is making a promise to himself here. He is determined that he will find the guilty man himself. This is quite a forceful statement indeed.
Finally, Reverend Mr. Dimmesdale's message to Hester is of great importance. He tells her to name the man who fathered her child. "Be not silent from any mistaken pity and tenderness for him," he says, "for, believe me, Hester, though he were to step down from a high place, and stand there beside thee, on thy pedestal of shame, yet better were it so than to hide a guilty heart throughout life." And Mr. Dimmesdale knows exactly what he is talking about.