Introduction
Asha Vahishta, "Best Truth" or "Best Righteousness" (later Ardvahisht), is one of the six Amesha Spentas, personifying asha, the fundamental principle of truth, order and righteousness that stands opposed to druj, the Lie, throughout Zoroastrian theology.
The Amesha Spentas ("Bounteous Immortals") are six (or, counting Ahura Mazda himself as their head, seven) divine beings who represent and administer aspects of Ahura Mazda's good creation. Zoroastrian theology generally treats them as emanations or aspects of Ahura Mazda's own nature rather than as separate offspring in an ordinary genealogical sense, and each is opposed by one of the six chief daevas in Zoroastrian dualism.
Central concept of asha
Asha is arguably the single most important concept in Zoroastrian ethics and cosmology, denoting the truth, order and righteousness that Ahura Mazda chose at the beginning of existence, and that every believer is called to uphold through good thoughts, words and deeds. Asha Vahishta is the personification of this principle in its most perfect form.
Association with fire
Asha Vahishta is closely linked with fire, itself a central symbol of truth and purity in Zoroastrian worship, and fire temples are traditionally regarded as under his particular protection.
Opposing daeva
Asha Vahishta is opposed by Indra (as a daeva), one of the six chief daevas in the developed Zoroastrian system, who is said to lead people away from righteousness. This Indra shares his name with the god of the older, shared Indo-Iranian religious tradition, and with the Vedic and later Hindu Indra, though in Zoroastrianism his role has been inverted into that of a demon.