Because the outcome is contested in time even though it is assured at the end, Zoroastrian ethics carries an unusual weight. Human beings are not spectators to the conflict between truth and the lie; they are recruits, and their thoughts, words and deeds materially strengthen one side or the other. The threefold formula of good thoughts, good words, good deeds is not a summary of pious sentiment but a description of how the war is fought.
Several consequences follow. Asceticism has no place: the material world is Ahura Mazda's good creation and is to be cultivated, not renounced, so agriculture, marriage, honest trade and the care of useful animals are religious acts. Celibacy and fasting, virtues in several neighbouring traditions, are not virtues here. Pollution is taken seriously as the incursion of the hostile power, which explains the elaborate purity code and the practice of exposing the dead rather than burying or burning them, since a corpse must not defile earth or fire.
The historical question of influence on Judaism, Christianity and Islam is genuinely contested and worth stating carefully. Jews encountered Persian rule from the sixth century before the common era onward, and the features that appear in Jewish literature in and after that period, a named adversary, ranked angels, a final judgement, bodily resurrection and a world made new, are all prominent in Zoroastrianism. Some scholars regard the influence as substantial and demonstrable; others point out that the Zoroastrian texts describing these doctrines in developed form were written down centuries later than the Jewish ones, so that the direction of borrowing cannot be established from the manuscript evidence alone. The dating of Zarathustra himself is unsettled, with proposals ranging across a millennium. The parallels are not in dispute; what they show is.