It is classified as a Samanya Upanishad and attached to the Rigveda. The Mudgala Upanishad, along with Subala Upanishad, is one of the two Upanishads that discuss the Purusha Sukta of Rigveda. It is notable for asserting that Narayana (Vishnu) is the Brahman (Highest reality, Supreme being), that he created the universe from a fourth part of himself, then became himself the Atman (soul) in individual living beings. The text asserts that Narayana is Moksha (liberation), representing the state of union between the Atman and the Brahman. The text is notable in that it presents only the first nine verses of the Purusha Sukta, and the absence of last seven verses that describe the creation of living beings and varna (social classes).