One of the most prominent themes in A River Sutra is love. The Narmada River is depicted as a lover on a journey to meet her groom, the Lord of the Oceans. Through each story the unnamed narrator encounters, he gains understanding of what his friend Tariq Mia describes as the mysteries of the human heart. The types of love that resonate with the heart are as varied as the stories of the Narmada River. The narrator learns about a monk whose love extends to all living creatures. This Jain monk, committed to the principle of "ahimsa" or nonviolence, tries to empathize with the suffering of every being, from the smallest insect to his wealthy father. In his quest to abandon his own emotions and absorb the world's pain, the monk realizes his once cold heart has warmed. Master Mohan becomes infatuated with a blind boy singer, moved by the purity of the boy's voice. In caring for the boy, Master Mohan shows selflessness, acting as a true father who prioritizes the boy's happiness over his own needs. After the boy's tragic murder, it seems inevitable that Master Mohan would take his own life. Similarly, the courtesan's daughter ends her life following her lover's death. The narrative suggests that some loves are so overwhelming that life feels unbearable without them. However, other forms of love offer the strength to keep living and persevering. The affection that the ascetic Naga Baba feels for his ward Uma motivates him to return to the world and abandon his ascetic lifestyle. Once Nitin Bose recovers from the madness caused by his unusual longing for a mysterious woman and eventually lets go of that desire, he too is able to rejoin the modern world. The narrator himself seems never to have explored his own capacity to love. As a mere observer, he appears only capable of listening to the stories and watching the Narmada River pass by.

At the beginning of the story, we learn that the narrator has decided to retreat from modern life. Instead of pursuing advancement in the bureaucracy where he is employed, he chooses to become the caretaker of a government rest house. Renunciation, a key concept in Indian religions, plays a central role in the novel. The narrator admits that his retreat from the world is modest compared to that of true "vanaprasthi," those who have withdrawn to the forest for contemplation. He confesses, "I knew I was simply not equipped to wander into the jungle and become a forest hermit, surviving on fruit and roots." Yet, this is exactly the journey many people he meets have undertaken. The Jain monk, who was once extremely wealthy as the son of a diamond merchant, left that life in search of enlightenment. Similarly, the Naga Baba, formerly a respected archaeologist, chose to live in rags and cleanse himself with the ashes of the cremated. The narrator struggles to understand why these men would choose such difficult and humbling paths. While Mehta does not harshly criticize these ascetics, the narrative suggests that true enlightenment arises from love. To genuinely love, one must remain engaged with the world. The Naga Baba's eventual decision to return to society as Professor Shankar hints at a more positive outcome than what likely awaits the Jain monk. The narrator imagines one day seeing the monk's frail body floating down the Narmada River. In his pursuit of enlightenment, the monk might ignore his physical needs and risk starving to death.

The theme of isolation is intimately connected to renunciation. Yet, those who experience isolation in the novel have not...