Intriguing question! In the book Uncle Tom’s Cabin by Harriet Beecher Stowe, Stowe utilizes several different techniques to illustrate the incompatibility of slavery with the Christian ethics of love and tolerance. For example, she utilizes the characters in the story and a direct address to her audience to illustrate this incompatibility.
Beginning with the characters in the story, Stowe utilizes multiple characters to demonstrate that slavery and Christianity’s ethics of love and tolerance are not compatible. For example, this is clearly seen in chapter nine. In this chapter, Senator Bird and Mrs. Bird discuss the issue of runaway slaves. Senator Bird illustrates that according to the law, people should not help runaway slaves. However, Mrs. Bird reveals that a Christian could not agree to such a law because the Bible illustrates that:
“I must feed the hungry, clothe the naked, and comfort the desolate; and that Bible I mean to follow."
Thus, she would not listen to the law because of her convictions from the Bible.
Furthermore, Stowe also uses a personal and direct address to her audience (at the end of the book) to illustrate that slavery and Christian ethics of love and tolerance are not compatible. For example, Stowe illustrates her shock that Christians could agree with the Fugitive Slave Act of 1850. As Stowe herself states:
"But, since the legislative act of 1850, when she [Stowe] heard, with perfect surprise and consternation, Christian and humane people actually recommending the remanding escaped fugitives into slavery, as a duty binding on good citizens,—when she heard, on all hands, from kind, compassionate and estimable people, in the free states of the North, deliberations and discussions as to what Christian duty could be on this head,—she could only think, These men and Christians cannot know what slavery is; if they did, such a question could never be open for discussion."
Lastly, she encourages Christians to help the slaves (at the end of her book). For example, she illustrates that Christians should open their doors to slaves, pray for them, and even help educate them.
Consequently, Stowe utilized her characters and her direct address to her audience to illustrate that Christian ethics and slavery are not compatible. Not only this, but she also encouraged her audience to act on this observation and help the slaves receive the help they deserved.