Harpo's girlfriend's father says that Harpo is not good enough to marry his daughter—Harpo is too young, he has very little money, and he comes from a bad family. Mr. ____ tells Harpo, later, why this is true: because Harpo's mother (Annie Julia) was killed by her lover (not Mr. ____; another, unnamed man, with whom Annie Julia was having an affair). This murder caused a scandal for Mr. ____'s family, and many in town no longer wish to associate with them for this reason.
Once again, we see repeated the idea that a certain family is "not good enough" to be joined with another family through marriage. Shug's family was considered suspect by Mr. ____'s family, and Mr. ____'s family considered suspect by Celie's family. But it also seems that these romantic relationships persist, despite the disapproval of family members.
Harpo has dreams that his Annie Julia is being chased by her boyfriend, the man who killed her, and then is shot in the stomach. Harpo wakes up from the dreams yelling, and Celie comes to him in the night to comforts him.
Annie Julia's violent death has obviously greatly affected Harpo, who is the most sensitive of Mr. ____'s children. But only Celie is empathetic enough to see this trauma in Harpo.
People say that Celie is skilled with Mr. ____'s children, but the three children other than Harpo are mean to her, and they do no work. Bub, a younger son, is always getting into trouble with the local authorities.
We hear very little from Bub, only to learn, much later in the novel, that he spends significant time in prison, and never amounts to anything in life, as he is always getting into scrapes with the law.
Harpo says he is in love with Sofia Butler, his girlfriend (the same girl whose father does not wish for them to marry). He declares, again, that he wants to marry her, and reveals that he has gotten Sofia pregnant. Celie tells Harpo that Sofia's father will be angry about this, but Harpo thinks the situation will improve once he and Sofia are married.
Harpo seems to believe that Mr. ____ will somehow come to understand Harpo's position if he sees how happy he and Sofia are together. But Harpo underestimates Mr. ____'s cruelty. In fact, Mr. ____ might oppose the marriage simply to spite and torment Harpo.
Sofia, seven months pregnant, comes to the house with Harpo to meet Mr. ____. Mr. ____ asks who the father is, trying to insult Sofia; she replies, calmly, that Harpo is the only possible father. Mr. ____ seems not to believe that this is true.
Here is an example of Mr. ____'s spitefulness. Although he knows full well that Harpo is the father, he wishes to test Sofia, and, if possible, to insult her.
Mr. ____ says he will not let Sofia and Harpo marry, even though Sofia is pregnant. Sofia says she doesn't need to be married at the moment; she is living with her sister and her sister's husband. She tells Harpo that once he is a free man (working on his own, and not living with his father), she and Harpo and their child can live together.
Sofia here demonstrates her strength as a woman and as the potential leader of a household. She does not rely on Harpo to provide for her. Instead, Sofia is a spur causing Harpo to work harder in the fields, and to contribute more to the family than ever before.