Chandogya Upanishad 6.4

yad agne rohitaṃ rūpaṃ tejasas tad rūpam yacchuklaṃ tad apām yat kṛṣṇaṃ tad annasya apāgād agner agnitvam vācārambhaṇaṃ vikāro nāmadheyaṃ trīṇi rūpāṇīty eva satyam

'The red colour of burning fire (agni) is the colour of fire, the white colour of fire is the colour of water, the black colour of fire the colour of earth. Thus vanishes what we call fire, as a mere variety, being a name, arising from speech. What is true (satya) are the three colours (or forms).

yad ādityasya rohitaṃ rūpaṃ tejasas tad rūpam yacchuklaṃ tad apām yat kṛṣṇaṃ tad annasya apāgād ādityād ādityatvam vācārambhaṇaṃ vikāro nāmadheyaṃ trīṇi rūpāṇīty eva satyam

'The red colour of the sun (âditya) is the colour of fire, the white of water, the black of earth. Thus vanishes what we call the sun, as a mere variety, being a name, arising from speech. What is true are the three colours.

yac candramaso rohitaṃ rūpaṃ tejasas tad rūpam yacchuklaṃ tad apām yat kṛṣṇaṃ tad annasya apāgāc candrāc candratvam vācārambhaṇaṃ vikāro nāmadheyaṃ trīṇi rūpāṇīty eva satyam

'The red colour of the moon is the colour of fire, the white of water, the black of earth. Thus vanishes what we call the moon, as a mere variety, being a name, arising from speech. What is true are the three colours.

yad vidyuto rohitaṃ rūpaṃ tejasas tad rūpam yacchuklaṃ tad apām yat kṛṣṇaṃ tad annasya apāgād vidyuto vidyuttvam vācārambhaṇaṃ vikāro nāmadheyaṃ trīṇi rūpāṇīty eva satyam

'The red colour of the lightning is the colour of fire, the white of water, the black of earth. Thus vanishes what we call the lightning, as a mere variety, being a name, arising from speech. What is true are the three colours.

etaddha sma vai tadvidvāṃsa āhuḥ pūrve mahāśālā mahāśrotriyāḥ na no 'dya kaścanāśrutam amatam avijñātam udāhariṣyati iti hy ebhyo vidāṃcakruḥ

'Great householders and great theologians of olden times who knew this, have declared the same, saying, "No one can henceforth mention to us anything which we have not heard, perceived, or known." Out of these (three colours or forms) they knew all.

yad u rohitam ivābhūd iti tejasas tad rūpam iti tad vidāṃcakruḥ yad u śuklam ivābhūd ity apāṃ rūpam iti tad vidāṃcakruḥ yad u kṛṣṇam ivābhūd ity annasya rūpam iti tad vidāṃcakruḥ

'Whatever they thought looked red, they knew was the colour of fire. Whatever they thought looked white, they knew was the colour of water. Whatever they thought looked black, they knew was the colour of earth.

yad v avijñātam ivābhūd ity etāsām eva devatānāṃ samāsa iti tad vidāṃcakruḥ yathā nu khalu somyemās tisro devatāḥ puruṣaṃ prāpya trivṛt trivṛd ekaikā bhavati tan me vijānīhīti

'Whatever they thought was altogether unknown, they knew was some combination of those three beings (devatâ). 'Now learn from me, my friend, how those three beings, when they reach man, become each of them tripartite.'