June the 25th is the feast of IMMORTALITY “ameretát” in the Avestan Calendar.
In the Indo-European poetry it is a basic feature of the god beings that they are “immortal and destined for eternity.”
Ameretát “immortality, deathlessness” is one of the virtues/god-powers of Mazdá in the poetic gathas.
In the Younger Avesta, the “ahûrás of mazdá” are simply referred to as amešá or amertá “immortal, undying, unfading (*n̥mr̥to-)” with the title speñtá “bright, auspicious.” Together referred to as amešá/amertá speñtá “the auspicious immortals.”
In Avestan, the idea of “the sacred” speñtá is that of “an auspicious and bright force swollen with abundant energy and unfading vitality.”
The “Sacred/Auspicious Immortals” are constantly invoked in the poetic gathas, they are virtues/god-powers and guardian saints of the elements in the physical realm. They teach the mortal men to become “Immortals, un-ageing, un-decaying and undying.
For in contrast to the Immortals, the humans are called mortals “mašyá/martyá” in the poetic gathas. (The Persian word for man “mard” and “mardom” people, refers to the mortality of mankind and comes from this Avestan root.)
In Zoroastrianism, the Auspicious Immortals inspire mortals with a “superhuman force” to be just like the gods. As we read in the poetic gathas, Yasna 48.1, 3rd rhymed verse line “Immortality will triumph over demonic forces and mortal men.”
For demons, death and mortality represent limitation. But the “unfading energy of mind-power/passion unleashed,” represents “Mazdá.”
Mazdá and his ahûrás “supreme virtues/god-beings” will remake the creation in brilliance and inspire it to be undying, un-ageing and immortal.
The unfading passion/mind power, the genial, creative ideas; are immortal and undying. Per the Zoroastrian doctrine, it is the destiny of mortals to become immortals. We are destined to manifest the genial, creative ideas in the physical form, to evolve into a new body and become immortal in flesh. The journey of consciousness will never end neither does the evolution of man.
The godlike supermen of Ahûrá Mazdá, will reshape the world in splendid excellence, and make it un-ageing, undying, un-decaying, eternal and forever young, as is in the ideal (vasö/wish for) dominion. (Yašt. 19. 11).
ýat kerenavãn frašem ahüm
azarešeñtem amarešeñtem
afrithyañtem apuyañtem
ýavaæ-jim ýavaæ-sum vasö-xšathrem
ardeshir
Authentic Gatha Zoroastrianism 
Mr. Ardeshir, you wrote “In Zoroastrianism, the Auspicious Immortals inspire mortals with a “superhuman force” to be just like the gods”… But you really mean “gods”? In the plural? But, Ahûrá Mazdá is not the only god? I thought Ameretat and other speñtá was not gods!
Ameretát “immortality, unfading energy” is one of the ahûrás “god-beings” of Mazdá, “passion/mind-power unleashed.”. The religious poetry of the poetic gathas unfolds into a multiplicity of ahûrás or god-beings. The gathic poetry shows the god-force as both Singular and simultaneously Plural (Mazdá and his ahûrás) See Yasna 30.9 and Yasna 31.4. Among other ways that the multiplicity and unity of the god-force is demonstrated, is by the simultaneous address to Thou and You in numerous sacred gathic verses. However, the multiplicity of ahûrás or god-beings is always accompanied by a clear recognition that ultimately the many ahûrás are only names for the different aspects of Mazdá “the creativity and originality of mind-power, spirit, passionate will.”
Yet, it is of paramount importance to add that in the entire poetic gathas, the whole Avestan lore or anywhere in the ancient Zoroastrian literature there is NO TRACE of a shema or adonai echad like formula such as Deuteronomy 6: 4-9.
A very nice positive, almost poetic, piece of writing, Ardeshir, very nice to read this