Throughout her life, Jane has been instructed in duty: at Lowood School, at Thornfield, and now while she lives with the Rivers family who have rescued her from starvation, a family who turns out to be her relatives. And, so, the theme of duty is continued as her cousin St. John Rivers presses Jane to marry him and join him as a missionary to India. When Jane refuses his proposal, the mood changes from the festive one of Christmas and Jane's happiness at the beginning of the chapter--
I had long felt with pleasure that many of my rustic scholarJanes liked me....Deep was my gratification to find I really had a place in their [her students'] hearts....
However, when Jane informs St. John that she is soon to depart, he is dissatisfied and appeals to her sense of duty, chiding her for being selfish:
"Jane, I excuse you for...pleasing yourself with this late found charm of relationship but then, I hope you will begin to look beyond Moor House and Morton, and sisterly society, and the selfish calm and sensual comfort of civilized affluence. I hope your energies will then once more trouble you with their strength.”
Jane contradicts him, saying that she has a right to be happy. And, she remains in this mood as the evening is festive, as is the following week. Nevertheless, as time passes, Jane feels that St. John "took away my liberty of mind." For, he scorns vivacity; thus Jane experiences a restraint of her natural inclinations. In short, St. John is repressive and Jane sobs during one of their encounters in which he asks Jane to accompany him to India. She begs him, "St. John...have some mercy!" But, he scolds Jane, telling her to be humble and obey; Jane feels as though an "iron shroud" forms around her. So, she begs him for time before she answers.
Later, Jane agrees to accompany St. John, but not to marry him. "Adopted fraternity will not do," St. John responds, and Jane is again dismayed. Finally, she reacts against him,
“I scorn the counterfeit sentiment you offer: yes, St. John, and I scorn you when you offer it.”
St. John reacts with coldness and Jane is left feeling as if he has "knocked" her down. From her festive Christmas mood at the beginning of the chapter, Jane is reduced by St. John's demeaning attitude to feeling demeaned and repressed.