Asha Vahishta (Best Righteousness), the second entity was originally called Arta to begin with-the Indian Rita-and later Ashavahisht, the better Asha Vahishta. He is the protector of fire, the seventh creation, which immediately reveals his nature. As guarantor of the moral and physical order of the world, his chief adversary is the demon world.
The domain of Asha Vahishta as protector of fire becomes more significant with the recognition of the importance of fire in the ancient Iranian culture. Fire was an essential element by which oaths were sworn; and it was believed to be an effective protection against demons. Fire was a supreme religious cult object causing the Persians to be called "fire-worshippers" by outsiders. It is felt that this unique characteristic kept Mazdaism persevered and not invaded by an abstract faith.
Asha Vahishta and Vohu Manah were closely associated, although the latter was higher in rank, and Asha Vahishta was more concerned with the order of the cosmos than with human order.
Asha Vahishta's feast day, "New Day," in Persian "No Ruz," was the celebration of the seventh creation, fire, and was set apart; being it preserved their life-force. Apparently Zoroaster established the feast at the spring equinox, re-dedicating what probably had been an ancient celebration of spring to Asha Vahishta and fire. A.G.H.
Boyce, Mary, Zoroastrians: Their Religious Beliefs and Practices, New York, Routledge, 2002, pp. 22, 33
Grimal, Pierre, Larousse World Mythology, Secaucus, New Jersey, Chartwell Books, 1965, p. 190