There is a verse in the Brihadaranyaka Upanishad which says,
Indra, through Maya, appeared as many forms. [1]
It has been quoted by both Gaudapada and Shankara to illustrate how, through the illusion of Maya, Brahman appears as many. With knowledge of Advaita, this illusion is dispelled.
The full verse says,
He shifted shape to match every shape, to manifest his shape. Indra, through Maya, appeared as many forms. his horses, hundreds and ten, are yoked.
Though quoted in Advaita literature, the verse is, itself, a quote — from the Rig Veda [2].
In addition to conveying the fundamental teaching of Advaita, the mantra is significant for its reference to Maya, showing its Vedic origins and the continuation of its meaning. This is why it was later quoted in the Upanishads and then by Gaudapada and Shankara.
The Brihadaranyaka Upanishad reveals its meaning at the end of the passage it features in,
He is the horses; he is ten, many thousands, and infinities. He is Brahman, without a before, without an after, without an inside, without an outside. This Self, all-embracing, is Brahman. That is the teaching.
Ultimately, Indra, just like everything else, is Brahman. However many forms there are, they are all Brahman.
Gaudapada refers to Indra’s ‘Maya’ in his Mandukya Karika,
From such Scriptural passages as, “There is no multiplicity in Ātman”, “Indra through Māyā”, we know that the Ātman, though ever unborn, verily appears to have become many (only) through Māyā. [3]
Shankara, commenting on this verse, uses it as scriptural evidence for teaching the illusory nature of the “existence of duality”,
such Scriptural texts as, “In this (Ātman) there is no multiplicity,” … negate the existence of duality. Therefore creation (imaginary) has been imagined in order to help the understanding of the non-duality of Ātman… this is further borne out by the use of the word, “Māyā” denoting unreality (in connection with creation) in such Scriptural texts as “Indra through Māyā assumed diverse forms”. [4]
This means creation implies “diverse forms” and duality. There is the appearance of many created things, but it is only appearance. In reality, the Self is indivisible, hence there is “no multiplicity”.
Shankara cites ‘Indra’s Maya’ in his commentary on another of Gaudapada’s verses in the Mandukya Karika which says,
As are dreams and illusions or a castle in the air seen in the sky, so is the universe viewed by the wise in Vedānta [5]
Shankara explains,
As an imaginary city in the sky…though appearing real to us, is seen to vanish suddenly as dream and illusion, which are known to be unreal (though they appear to be real)—so also is perceived this entire duality of the universe to be unreal. Where is this taught? This is thus taught in the Vedānta Scriptures. “There is no multiplicity here.” “Indra (assumed diverse forms) through the powers of Māyā.” [6]
He makes it clear that it’s not that the universe doesn’t exist, but that it’s not separate from us, it’s not a separate ‘thing’ and there are not two things (called ‘us’ and ‘universe’). Saying it’s an illusion means the “entire duality of the universe”. This teaching is often misunderstood as treating it as an illusion while still perceiving it and ourselves as separate. Therefore, the Maya has not been seen through and is confused with reality.
The Brihadaranyaka Upanishad, Gaudapada and Shankara all elucidate the ultimate teaching of the mantra. This can also be unpacked from exploring the verse itself. For example, the meaning of —
his horses, hundreds and ten, are yoked.
What does this mean? Firstly, the word for horse, hari, has a double-meaning — it also means “ray of light”. Secondly, “hundreds and ten” neither refers to one-hundred and ten, nor two separate numbers. A hundred times ten is a thousand. The thousand rays of light are “yoked”— grasped, in union with or identical to oneself [7].
The reference to a thousand, itself, is not literal but used to signify abundance, a large number or infinity. This is why the Brihadaranyaka Upanishad says Indra is “many thousands, and infinities.” It is no different to saying “He is Brahman” — “without a before…after…inside…outside.”
Alternatively, Shankara interprets the number ten as referring to the sense-organs,
Him ‘are yoked,’ like horses to a chariot, ten organs — called ‘Hari’ because they draw — nay hundreds of them, for the purpose of revealing their objects; ‘hundreds,’ because there are a great many beings. Since there are a large number of sense-objects (the Supreme Self appears as manifold). It is to reveal them, and not the Self, that the organs are yoked. [7]
Their restraint is indicated by the larger numbers of ‘hundred’ and ‘a thousand’ and ‘infinity’. They reflect the expansion of awareness which is the result of controlling or ‘yoking’ them, or more commonly, Yoga, the highest state, as defined by Katha Upanishad [8].
[1] 2.5.18
[2] 6.47.18
[3] 3.24
[4] Mandukya Karika Shankara Bhashya 3.24
[5] 2.31
[6] Mandukya Karika Shankara Bhashya 2.31
[7] Brihadaranyaka Upanishad Shankara Bhashya 2.5.18
[8] 6.10-11: “When the five organs of perception [senses] become still…that is called the highest state. This firm holding back of the senses is what is known as Yoga.”