Historical investigation so far, in trying to establish the origin of radical dualism, has traced it back to one of the great Oriental religions. That is the Persian religion of Zoroaster. A fundamental idea of Zoroastrism is that of a combat between two opposite worlds, and this duality extends far beyond the limits found in most other religions.
Conditions, as we see them in the world today, are the result of that gigantic struggle between two antagonistic principles--the principle of good and the principle of evil. The principle of good is represented by Ormuzd (Ahura Mazda), whose symbol is light. The principle of evil is represented by Ahriman (Angra Mainyu), whose symbol is darkness. Ormuzd has created the world, but his work is constantly counteracted by Ahriman, "the spirit of destruction".
In this fight against Ahriman, Ormuzd is assisted by the archangels, but Ahriman, too, has his helpers. In fact, all living beings in the world may be divided into two huge armies fighting each other without mercy and without a moment's interruption. That universal fight, however, is also reflected in the human soul. Man's personality is endowed with a supra-sensitive element by means of which, even before entering upon the scene of this earth, he has already made his option for good or evil. His entire destiny after his birth is dependent upon that fateful decision.
It should be admitted that there seems to be some limit, after all, to the radical character of this dualism of good and evil. The great conflict between the two powers is not destined to last eternally. At the end of the ages Ormuzd will win a final victory over evil. Then good men will be separated from evil men. After a great conflagration, destined to cleanse the world, all men will be reconciled under the sign of the great God Ormuzd.[1]
Note: