In what chapter of To Kill a Mockingbird does Atticus agree to take Tom Robinson's case?

The book is
unlike the film, because we don't actually see Judge Taylor approachand ask him to take the
case. Instead, the first mention of him accepting the case is whenhears kids at school saying
terrible things about her father. She comes home from school and questions Atticus, who
responds:

Atticus sighed. Im simply defending a Negrohis
names Tom Robinson. He lives in that little settlement beyond the town dump. Hes a member of
Calpurnias church, and Cal knows his family well. She says theyre clean-living folks. Scout, you
arent old enough to understand some things yet, but theres been some high talk around town to
the effect that I shouldnt do much about defending this man. Its a peculiar caseit wont come to
trial until summer session. John Taylor was kind enough to give us a postponement€¦

Later, in , we learn the important detail that Atticus was
assigned the case; he did not volunteer. This illustrates the sacrifice
that Atticus made by truly defending Tom Robinson. He didn't have to; he had a perfect
opportunity to blow it off and keep the town happy. But Judge Taylor assigned him the case
specifically because he knew that Atticus would do the right thing. In this chapter, we
read:

Lemme tell you somethin€˜ now, Billy, a third
said, you know the court appointed him to defend this nigger.

Yeah, but
Atticus aims to defend him. Thats what I dont like about it.

Atticus shows what a true defender of the law he is by truly defending Tom
Robinson.