Devas became arrogant because of their victories disregarding the fact that they obtained it only due to Brahman. Brahman therefore appeared before them to test them
The Brahman won a victory for the Devas and in that victory of the Brahman the Devas attained glory. They thought ‘the victory is ours and this glory is ours alone.’ He (Brahman) knew this notion of theirs and appeared before them. What that Great Spirit was they did not know.
- Verses 14–15, part 3, Kena Upanishad.
The devas sent Agni to find out who this person was. Brahman put forward a straw and asked Agni to burn it if he can. Agni tried but failed miserably
They addressed the Fire thus “O Jataveda! Find out what this Great Spirit is.” He said “yes.” He ran to That. That said to him “who art thou?” He replied “I am Agni or I am Jataveda.” That said “what power, in thee so named, is lodged.’ He replied “I can burn even all this, on the earth.” That (Brahman) placed a straw before him and said: ‘Burn this.’ He approached it with all haste but was not able to burn it. He immediately returned from thence to the Devas and said I was not able to learn what this Great Spirit is.”
- Verses 16–19, part 3, Kena Upanishad.
The devas sent Vayu to find out who this person was. Brahman put forward a straw and asked Vayu to blow it away if he can. Vayu tried but failed miserably
The Devas then said to Vayu: “Learn O Vayu! what this Great Spirit is” He said: “yes.” He ran to That. That said: “who art thou”? lie replied: “I am Vayu or Matarisva.” That said “what power is in thee; so well known?” He replied: “I can blow away all the universe and all that is on the earth.” That (Brahman) placed a straw before him and said “Blow it away.” He approached it with all speed but was not able to blow it. He returned immediately from there and told the Devas “I was not able to learn who this Great Spirit is.”
- Verses 20–23, part 3, Kena Upanishad.
Finally, the devas send Indra to find out the person’s identity. As he approached, Indra saw the great Uma Parvati beside the man. She revealed that the man was Brahman himself
Then they said to Indra: “Maghavan! learn what this Great Spirit is.” He said “yes” and ran to That. That vanished from his view. He beheld in that very spot a woman, Uma, very beautiful and of golden hue, daughter of Himavat. He said to her “What is this Great Spirit?” She said “It is Brahman indeed. Attain glory in the victory of Brahman.” From her words only, he learned that it was Brahman.
- Verses and 24–26, Part 3 and 4, Kena Upanishad.
Because Indra realised the Brahman, he became the best among the devas
These Devas Agni, Vayu and Indra therefore much excel others, because they touched the Brahman nearest. They it was who first knew the Spirit to be Brahman. Therefore also does Indra considerably excel other Devas because he approached Brahman nearest and because he first knew the Spirit to be Brahman.
- Verses 27–28, part 4, Kena Upanishad.