How do the missionaries change the Igbo tribe and how does Okwonkwo react to it?

In Christianity, Nwoye finds comfort for things that have long disturbed him. But the religion also provides him with a way to rebel against his father. And the social effects of Christianity will be as bad as the Igbo fear. The new religion undermines the hierarchies of the culture; Achebe also points out that the religion provides hope to those who have suffered under Igbo law. Although the men without title embracing the religion says little in favor of it (especially since Igbo society has a high degree of social mobility), Nneka's defection to the new faith is telling. She has born four pairs of twins, and has been forced to throw all of them away. Pregnant again, she is desperate to save her children. Not coincidentally, she bears the name that Uchendu mentioned earlier: "Mother Is Supreme."

But just as Igbo faith is integral to Igbo society, the new religion also comes with social and political attachments. Once land has been granted for the building of the church, the whites become difficult to dislodge. They bring their laws and their guns soon afterward, and Igbo men and women are forced to live under the colonial yoke.

Okonkwo is not a man who learns. He cannot understand that his own harshness has driven Nwoye away. The boy is terrified of him, and he has suffered greatly because of his sensitivity. He cannot understand that the new religion offers sanctuary to the oppressed in Igbo society. Okonkwo is blind with rage. He only wants to see the church destroyed and the white men driven out or killed.