`As clouds of smoke proceed by themselves out of a lighted fire kindled with damp fuel, thus, verily, O Maitreyi, has been breathed forth from this great Being what we have as Rig-veda, Yagur-veda, Sama-veda, Atharvangirasas, Itihasa (legends), Purana (cosmogonies), Vidya (knowledge), the Upanishads, Slokas (verses), Sutras (prose rules), Anuvyakhyanas (glosses), Vyakhyanas (commentaries). From him alone all these were breathed forth.