ِ About Two Avestan Compounds aǝm.mǝrǝṇcō و upā.θβaiieiti in Vishtasp Yasht

The Avestan version of Vishtāsp Yasht is part of a late Avesta and consists of eight Fragards and sixty-five verses. In This Yasht, Zarathushtra concisely teaches the principles of religion to Vishtasp addressing by "O my son" as Ormazd does to Zarathushtra in the nineteenth Fragard in Vendidād. Vishtāsp Yasht presumably belongs to the second Nask of twenty-one Nasks of Sasanid Avesta named Vishtāsp Sāst from Hādagmānsarig class. What we call it Vishtāsp Sāst does not exist now and the abstract that we can find in eighth Fragard of Dinkard is too incomplete. Nevertheless, it allows us to inform on its content. According to eighth Fragard of Dinkard Vishtāsp Sāst relates to believing of Vishtāsp in Zarathushtra's religion and subjects relevant to it. Zarathushtra, the messenger, for reporting his task according to Ormazd's request, offers the needed knowledge to Vishtāsp. Then Ormazd sent Amahraspands to testify the truth of Zarathushra's message and also to show Vishtāsp what he will obtain with accepting Zarathushtra's religion. This acceptance results in Arjāsp's opposition. Arjāsp, who was provoked by anger, starts a war against Vishtāsp. The narration of this war which has been reported in Vishtāsp Sāst is missed in the existing text titled as Vishtāsp Yasht. In the other hand, according to the abstract which we know according to the eighth book of Dinkard, the narrative of the pious man and also wicked man after death which allocates the eithth fragards of Vishtāsp Yasht and has many resemblences with the second fragard of Hādokht Nask, does not exist in Vishtāsp Sāst.
For many years, Avestan scholars have thought that the Avestan text of Vishtāsp Yasht is very new; Even newer than Vendidad, which Skjærvø (2007: 112ff) considers its time to be later than Yasna and Wisperad and in the partian period. The common sentences and phrases that Vishtāsp Yasht has with the Vendidad-e-sade have made Darmesteter consider it just a text of a combination of Vendidad sentences and phrases and an imitation of it. According to Darmsteter (1962: 324-325), Vishtāsp Yasht is not original, and is entirely borrowed from Vendidad and some other parts of Avesta. Mole (1963: 650) describes the linguistic structure of the Avestan text Vishtāsp Yasht as the most inaccurate among the existing Avestan texts, and according to the linguistic features of this text, he believes that Vishtasp Yasht is not only a part of the Achaemenid dynasty of Avesta, but also a part of the Sassanid dynasty. However, Mole does not accept Darmesteter's view either, and does not see this text as the result of the accidental juxtaposition of borrowed passages from other parts of the Avesta. Mole believes that Vishtāsp Yasht has practically all the elements in the narration of Vishtāsp Sāst: encouraging acceptance of religion, visiting Amahraspands, promising of blessing and victory, teaching religion, and revealing the reward after death. In contrast, what is lacking are details with narrative characteristics: the description of the coming of Amahraspands, the battle with Arjāsp, and so on. Mole is of the opinion that Vishtāsp Yasht probably indicates the adaptation of the content of Vishtāsp Yasht's myths to a prayer application (Mole, 2016: 413).