The Chaturveda Upanishad 

The Chaturvededa Upanishad is a lesser-known Upanishadic text that explores the origin of the four Vedas and their ultimate unity in the supreme cosmic principle, Lord Nârâyana. It is a very short text, consisting of only about eight verses. It bridges the concept of the four Vedas—Rig, Yajur, Sama, and Atharva—with the supreme creator and absolute reality. It describes a contemplative inward vision, depicting a universal, all-facing flame of fire situated within the heart center as the essence of the divine person who sustains the universe. 

The text worships and centers upon Lord Nârâyana as the eternal, infinite Supreme Being from whom creation emanates. It describes how existence began with Nârâyana, before the traditional cosmic elements, gods, earth, or heavens came to be. The text symbolically maps the four Vedas and their sacred meters to the directional faces and meditative chants of Brahmâ, originating from the supreme source:

• Rig Veda: Associated with the eastern face and the Gâyatrî mantra.

• Yajur Veda: Associated with the western face and the Vyâhriti.

• Sama Veda: Associated with the melodic chanting source of the universe.

• Atharva Veda: Associated with the southern face and the Anushtubha chant.

The gods, having reached heaven, question Rudra and praise him with raised arms as the all-formed (viúvarûpa), the one Brahmâ who is dual and triple, peace itself, both offered and unoffered, given and ungiven, all and non-all, etc. The text ends with a hymn-like passage invoking the great Devourer (mahâgrâsa) who swallows the subtle and the gross, and the colophon.

A short passage describes the heart-lotus (inverted, like a downward-facing bud) in which a great fire burns; within its flame resides the Paramâtman, who is Brahmâ, Îsâna, the Imperishable, the supreme Self-ruler (svarâm). It is said to equal the merit of 60,000 recitations of the Gâyatrî, thousands of Itihâsa-Purâna recitations, and 10,000 repetitions of the Pranava (Om). It purifies a lineage up to seven generations and, through its recitation (jâpya), leads to immortality.

This is a brief, theistic (primarily Vaishnava-leaning with Nârâyana as the primordial source) text that links the four Vedas to the four faces/directions of Brahmâ while subordinating Brahmâ to Nârâyana. It emphasizes the purifying and liberating power of its own study rather than elaborate philosophical inquiry. Like many minor Upanishads, it combines creation myth, Vedic etiology, heart-meditation imagery, and phala-shrruti.