Justice
The Land family questions the concept of justice throughout the novel. First, there is the injustice of the family's debacle with Israel Finch and Tommy Basca and the consequences of dealing with them: loss of innocence, Jeremiah's firing and healing of Mr. Holgren, and Davy's escape. Reuben describes the injustice he feels in the courtroom and when he reads the unfair descriptions of Davy in the newspapers. Perhaps the biggest hurdle the Lands face is deciding whether the pursuit of Davy is just - Reuben struggles with the idea of his brother being brought to justice in court but he also cannot bear the idea of never seeing him again.
The West
Swede is obsessed with everything that has to do with Westerns: horses, Western novels, and cowboys such as Butch Cassidy. Her tenacity for the West bleeds into the rest of the Lands as they go west in search of Davy. For the Lands, the West is mysterious but holds the hope and promise of finding Davy.
Loyalty
The Land family is loyal to each other. Reuben is heartbroken when he feels that he has ruined Davy's chances of winning the trial so he and Swede make a plan to break their older brother out of jail. When Davy breaks out on his own, the rest of the Lands uproot their entire lives to chase after him. Reuben and Swede are especially loyal to each other and Reuben feels conflicted when he does not tell his sister about seeing Davy. Reuben also struggles with Jeremiah's decision to work with Andreeson, because he feels that his father is betraying Davy.
The Enemy
In the beginning of the novel, Reuben can clearly define who his enemies are - Israel Finch, Tommy Basca, and eventually Andreeson. As the Lands go further into the Badlands after Davy, however, the idea of a singular enemy becomes less clear. Jeremiah agrees to work with Andreeson to find Davy and Reuben feels betrayed because he still wants to think of Andreeson as the enemy even after it becomes clear that the fed genuinely wants to help. Furthermore, Reuben continues to have difficulty defining whether Davy should be considered an enemy. Swede processes the enemies in her life - Tommy Basca and Israel Finch - through writing.
Faith
Jeremiah is a religious man, especially after surviving the tornado disaster and his faith seeps into the other family members. Reuben is often the only witness to his father's miracles and both of his children agree to go after Davy in a direction that is purely based off of Jeremiah's faith that he will find his son.
Sacrifice
Nearly all of the characters in Peace Like a River make sacrifices. Davy gives up his youth and freedom to protect his family from the town's delinquents. Jeremiah gives up his entire life in Roofing to pursue his Davy, regardless of the consequences. Reuben gives up his hard earned money to buy groceries instead of spending it on toys for Christmas.
Consequences
As a young narrator, Reuben comes to realize that all actions (or inactions) have consequences. He begins to understand this important theme when his brother's protection of his family lands him in jail and Reuben's own testimony ruins any chance of Davy winning in court. Because his loyalty to Davy, Reuben feels that he cannot tell Swede, his confidant, that he has seen his older brother. His refusal to share the news comes to a head when Andreeson goes missing and is feared dead.
