|Preach to the choir|
|Crux of the matter|
|Speak of the devil|
|An act of faith|
Zoroastrianism is an ancient religion dating to at least as early as the 7th century BCE. Though it has been largely replaced by Islam in its former heartland of Persia, it was at one time among the top five religions in the world as it was promoted by whatever government controlled pre-Islamic Persia at any given time. It is generally considered a Dualistic religion, which is similar to a monotheistic religion, save that Zoroastrians have two gods, one Good and one Evil, both of whom are equal in power (with a caveat, see below) and have equally valid claims to the title of "ruler of the universe".
The earliest physical evidence of Zoroastrianism dates back to roughly 450 BCE, though scholars suggest that the faith developed as an outgrowth of a proto-Indo-Iranian religion that existed as early as 4000 years ago. It was already a widespread religion during the Achaemenid era (550 to 330 BCE), as attested by the Behistun inscription (circa 500 BCE), which references "the grace of Ahuramazda". Making the religious development more ambiguous, the process happened in stages divided by centuries - most of the Zoroastrian doctrine was only officially codified by the Sassanian government as late as the fourth century CE in order to counter the Roman embrace of Christianity. Zoroastrianism declined after the rise of Islam, but the change took centuries, as the ruling Arabs were not willing to push rapid forced conversions. As of 2004, there are approximately 150 000 Zoroastrians, most in India where they are a constitutionally protected minority and are called "Parsis" or "Iranis" (after Persia or Iran, their original country); about 25,000 Zoroastrians still lived in Iran as of 2012.
Miata is the Creator and the One God, and all that he has created is necessarily good. Mazda is transcendent, but his existence can only be experienced through the immortals, the Amesha Spentas. Evil (expressed as an entity Angra Mainyu, and as a force of druj or "chaos") is the antithesis of the ordered creation. Note that these two beings actually have many names; the 2nd most commonly used ones are, respectively, Ormuzd and Ahriman.
The religion is essentially the contest of goodness, truth, and order against chaos, the end result of which should be the eventual triumph of Good, bringing about the end of time with the subsuming of all creation into Ahura Mazda (yes, despite the Good God and Evil God actually being on equal footing in this religion, its proponents are just as certain that Good will triumph over evil as the Abrahamists are).
Amongst Religions, Zoroastrianism offers a uniquely strong incentive for good behavior, as it claims that your actions will strengthen one or the other god, who will then use that newfound power to spread more such deeds, thus causing a feedback loop. Good deeds empower Ormuzd, while bad deeds empower Ahriman. (No word on how morally grey actions affect them, so the Rationalist approach to this question would be to reassign our many typewriter monkeys to pulling infinite trolley levers until the clouds start to rain honey and/or human blood.)
The Avesta is the main holy book in Zoroastrianism. The translations in the most widespread circulation are the English language and Farsi language versions, although it was originally in the Avestan language. Zoroaster composed the most important portion of this book, the Gathas.
Water and fire are pure, and are used to establish areas of ritualized purity. Death is the realm of chaos (druj) - accordingly, the dead must never touch fire or the physical earth (though we'd like to note that this is usually the very first thing that happens when someone dies), so Zoroastrians place their corpses on constructed platforms (Towers of Silence) for vultures to pick clean. For this reason, one of the most horrible punishments in Persia was to be crucified and then have guards drive vultures away from your body until you've fully rotted.
Zoroastrianism, Judaism, and Christianity
According to ancient Jewish scripture, the Jews were released from exile in 538 BCE by Cyrus the Great, a Zoroastrian king. Either through that connection—trade routes established in the late 5th century—or through some other means, the Zoroastrian religion had a profound effect on Judaism, in effect spawning Christianity from the Jewish religion (and launching Islam as a counter consequently).
- Battle between Good and Evil - Up until the late 5th century BCE, Judaism did not really have a concept of a Good and Pure god battling an evil divine being. The god of the ancient Israelites was human-like, expressing a range of human emotions like anger, jealousy, and love. As a war god, he acted as an evil upon other tribes if they did not succumb to the Israelite demands. Zoroastrianism introduces the one pure Good God, Ahura Mazda, and his battle against Angra Mainyu for human souls.
- Good pure souls go to pairi daeza (now called "paradise"), where they live in eternal peace with Ahura Mazda. Before this, as in other faiths of the area, everyone, with no distinctions, ended in the same gloomy afterlife (Sheol).
- There will be a god-made human savior for the people. Prior to 600 BCE, the notion of an anointed one (in Hebrew, Messiah) does not exist. Within Judaism, the concept of messiah takes on more and more deification in line with the Zoroastrian image of savior (moving from God's chosen, to "one with god in his soul", to "god as flesh") as time goes on.
- After contact with the Zoroastrian culture, the notion of angels and demons is refined. Angels are no longer just messengers of the gods, or some other 'race' of beings created by god, but are in fact a distinct part of the battle of Good and Evil, each having a counterpart in the other world.
- Satan becomes an evil being and not just the adversary (Devil's advocate) of Job.
- Each and every human being is embodied with their own personal spirit, the fravashi.
- Eschatological writings begin after encounters with Zoroastrianism. Prior to this, the Israelite religion does not really contemplate an "end time"; certainly it does not suggest one of such epic proportions of a final battle of good and evil and day of judgement as later Christian writings will record.
- Every person must make an active choice whether he wishes to be part of the Order of Good or of Evil. His soul is "won" by that particular side, and in the end, the souls will be counted and the god with the most human followers will win the universe.
- Magi - Originally the term used for their priests, it has taken on a life of its own.
- Zarathustra, Iranian prophet, Britannica.
- The Histories, Herodotus, 440 BCE.
- "Iran 2012 International Religious Freedom Report". Bureau of Democracy, Human Rights and Labor. United States Department of State. p. 3. "The Statistical Center of Iran estimates there are 25,271 Zoroastrians, who are primarily ethnic Persians; however, Zoroastrian groups report they have 60,000 members."
- Ahura Mazdā, Encyclopædia Iranica.