The Upanishads shift focus from ritual to introspection, introducing key concepts like “neti neti” and “Atman is Brahman.” They are dialogues between teachers and students seeking ultimate truth. In poetry, they inspire meditative and mystical verse that explores non-duality, the illusory nature of the world, and the silence beyond words. Poets quote or echo Upanishadic phrases to convey depth, often contrasting their abstract wisdom with the emotional richness of bhakti. They represent the intellectual heart of Hindu spirituality and a bridge between ritual and realization.

The Upanishads are a collection of philosophical texts that form the concluding part of the Vedic revelation (and are thus known as Vedanta, "end of the Vedas"). They shift the focus from external ritual to internal inquiry, exploring the nature of ultimate reality (Brahman), the self (Atman), and the identity between the two. Key concepts like karma, samsara, and moksha are fully developed here. For poets, they are a deep well of metaphysical poetry and profound spiritual insight.