What is the role of justice in Igbo society ?
One of the things that Chinua Achebe did in the novel Things Fall Apart was portray the nuanced way that crime and punishment worked in Igbo society. Many of the customs seemed to be primitive or arbitrary to other observers but Achebe showed the way that the "gods" worked to resolve conflicts and administer justice to villages and between villages.
In this way, justice was used as a way not only to resolve present conflicts but also to build connections between villages and to redress old wrongs. When Okonkwo killed one of his wives with his terrible gun, it could have been disastrous for him to be killed or jailed, so it made sense to banish him so that the village sees that he is punished but he eventually has the chance to return and rebuild what he lost.
Achebe also demonstrates perhaps that justice was sometimes flawed and particularly when Okonkwo goes against his friends' advice and takes part in killing Ikemefuna, the resulting trouble demonstrates some of the flaws in the justice system of the village.