"Oh, sure, he has reached the age of twenty-one, when we, civilized men, consider the male species has reached manhood, but would you call this—this—this a man? No, not I. I would call it a boy and a fool." (1.12)
The public defender is picking apart the word "man". First of all, he takes for granted that he and the jury are all "civilized men", but then he questions whether one birthday really makes someone a man. Then, he gives us two opposites to the concept "man": boy, and fool. The first one isn't too surprising; boys are often contrasted to men. But he also shows that he values intelligence in order to call someone a man.
"I don't want them to kill no hog," she said. "I want a man to go to that chair, on his own two feet." (2.29)
Miss Emma surely doesn't really think that Jefferson is a hog. She loves him and thinks of him as her dear boy. However, she knows that being a man has to do with the way that society sees Jefferson, and how he sees himself. That's what she wants to change.
"Do I know how a man is supposed to die? I'm still trying to find out how a man should live."
One important part of growing up is facing the fact that one day life is going to end. Grant still hasn't even figured out the right way to act like a grown-up, and what his responsibilities are to his community. He knows he'll have to figure those questions out before he can ever know how he's supposed to die well.
"I'm supposed to make him a man. Who am I? God?" (4.103)
Grant knows that helping someone grow up is hard enough, and that making them do it is next to impossible. It would take a miracle, in fact, to force an immature person to mature against their will.
"The public defender called him a hog, and she wants me to make him a man. Within the next few weeks, maybe a month, whatever the law allows—make him a man." (5.47)
The fact that Miss Emma chooses Grant to be the one to turn Jefferson, bibbidi-bobbidi-boo style, into a man, shows the power she believes a teacher has. She raised Jefferson and didn't manage to turn him into a man, but she is sure that the professor can do so.
"What she wants is for him, Jefferson, and me to change everything that has been going on for three hundred years. She wants it to happen so in case she ever gets out of her bed again, she can go to that little church there in the quarter and say proudly, 'You see, I told you—I told you he was a man.'" (21.86)
In this quote we see that coming of age isn't just something that an individual does. A whole society has to mature and grow. And when one race in particular has been at a disadvantage in that society through lack of education and enslavement, it is hard to expect a sudden change.
"And that's all we are, Jefferson, all of us on this earth, a piece of drifting wood, until we—each one of us, individually—decide to become something else." (24.48)
Grant compares Jefferson to a piece of rough wood that can be carved smooth into whatever he wants to be. The key is that each person has to decide to become something else—there's no whittler wandering around picking each of us up and telling us what to be.
Man walk on two foots; hogs on four hoofs. (28.17)
This is a sample of Jefferson's writing. This line is super-important because it shows us Jefferson drawing a line in the sand between man and beast. Now he just has to choose which one to act like.
"'Cause I'm go'n die soon? That make me a man, Mr. Wiggins?" (28.96)
Jefferson brings up a good, but difficult point. Mr. Wiggins wouldn't have paid any attention to Jefferson if he hadn't been sentenced to death. He would just end up like all of the other kids that graduated from Wiggins' classes. But his circumstances are extraordinary, so that requires Jefferson to mature extraordinarily.
tell them im strong tell them im a man good by mr wigin (29.40)
Jefferson, in his own words, has decided to grow up and let everyone else know it. Just before his death he has finally fulfilled everyone's wish and become a man.