What do you think the book title, Roll of Thunder, Hear My Cry means?

The title of Mildred Taylor's teen novel, Roll of
Thunder, Hear My Cry, comes from an old spiritual sung by slaves nearly a century
before. Mr. Morrison sings the song at the beginning of Chapter 11, a pivotal time of the novel
in which T.J. Avery is hunted down for the attack of the Barnetts at their Strawberry store.
Thunder is used as a metaphor throughout the novel (another purpose for the title), and Cassie's
emotional pleas for a semblance of respect and justice are echoed in the "Hear My Cry" portion of
the title. Thunder becomes even more important in the final chapters; in Chapter 11, the
"distant" and "approaching" thunder signals the onset of more trouble. In the final chapter, it
is thunder's accompanying force--lightning--that is presumed to have set the cotton fields afire,
and it serves as a powerful force of nature that unifies the men--black and white--at the
end.