Zoroastrianism is the religion of Cyrus the Great and his Dynasty, the Achaemenids. In Ezra the Bible makes it clear that Cyrus, while Zoroastrian, worships the God of Israel and was his instrument and annointed (Messiah), sent to deliver the Children of Israel, re-establish the Jewish Temple and basically civilise the world.
“…This is what Cyrus king of Persia says: The Lord, the God of Heaven, has given me all the kingdoms of the earth and has appointed me to build a temple for him at Jerusalem in Judah. Anyone of his people among you - may his God be with him, and let him go up to Jerusalem in Judah and build the temple of the Lord, the God of Israel, the God who is in Jerusalem. And the people of any place where they may still be living are to provide them with silver and gold, with goods and livestock, and with freewill offerings for the temple of God in Jerusalem…”
As you can see Cyrus, a Zoroastrian monotheist and not an idol-worshipping pagan like the Babylonians, worships the same God as YHWH, the God of Israel. Ahura Mazda (Wise Lord) is thus the same God as the God of Israel, according to the Bible.
Later on, the Magi who visited Christ were understood by the Fathers as Zoroastrians from Persia. Christianity is the fulfilment of Zoroastrianism. The Prophet Zoroaster predicted the coming of a Saoshyant (Saviour) who would usher in a New Age and the bodily resurrection of the dead. It is from Zoroastrianism, and not Judaism, that Christianity and later Judaism received such ideas as heaven and hell, the resurrection of the dead, good vs evil, the figure of the devil, light v darkness etc.
Zoroastrianism is thus highly important, since it intersects with revealed biblical religion.
Zoroaster is now considered to have lived about 2000 BC. Many scholars consider it to be the oldest recorded monotheistic religion. He could predate Moses and even Abraham. This means that he came before God chose the Jewish people. I therefore consider him to have been a true prophet, a man who received genuine visions from God. Remember that prior to the Covenant with Abraham, God concluded Covenants with Noah and gentile prophets.
“…And it came to pass, when the Lord Jesus was born at Bethlehem of Judea, in the time of King Herod, behold, magi came from the east to Jerusalem, as Zoroaster had predicted; and there were with them gifts, gold, and frankincense, and myrrh. And they adored Him, and presented to Him their gifts. Then the Lady Mary took one of the swaddling-bands, and, on account of the smallness of her means, gave it to them; and they received it from her with the greatest marks of honor…”
-* Syriac Infancy Gospel of the Saviour*
As this apochryphal (but Orthodox) Infancy Gospel tells us, one of the most important elements of the Christmas story was the “Manifestation” (revealing) of Christ to the world when the Zoroastrian priests, the Magi - representing the first Gentiles to welcome the Messiah and Saviour of Humanity into the world - followed the star of Bethelehem and with their advanced astronomical skills came to offer Christ gifts of gold, frankincense and myrrh (symbolizing the tripartite Zoroastrian creed of, “Good thoughts, Good words and Good deeds”).
Iranian Zoroastrians were thus the first Gentiles to accept Christ. They were the only Monotheists among the pagan religions of the Ancient World. There is a Syriac Church in Iran which claims to be the place where the group of Zoroastrian priests hailed from. It is a source of pride to Iranian Christians, who are suffering woefully under the current Islamist government in Iran.
‘Second Isaiah’ or ‘Deutero-Isaiah’ is the name of the chapters 40-55 of the Biblical book of Isaiah, which were added to the ‘real’ text of Isaiah. The second prophet predicts the coming of king Cyrus, who will liberate the Jews from their Babylonian Captivity and will bring them to the Promised Land. Cyrus was considered by the Jews a monotheist. This Jewish text confirms Cyrus’ own proclamation that he was chosen by the Supreme God to liberate Babylon and free the Jewish People.
Cyrus was an incredible man, the Persians/Iranians were and are still an incredible race of people and Zoroastrianism is an incredible religion.
Their holy text, the Zend Avesta is worthy studying.