Both men live in South Africa. By the end of the novel, both men have lost their sons. Also, both men want for nothing more than South Africa to become prosperous again.
Yet it is their differences which speak to Paton's desire for brotherhood and camaraderie. Jarvis has lost his son, Arthur, who was murdered. Unfortunately, it was Kumalo's son, Absalom, who murdered Arthur. Also, Jarvis is rich and white. Kumalo is poor and black. Given that both of their sons left for Johannesburg (another similarity), neither of the fathers know about the lives their sons lead there. Arthur has become an activist, and Absalom has wandered away from his religious upbringing—becoming an adulterer, thief, and murderer.