CR, yes, of course it is entirely possible that the Zoarastrians stole the idea from someone else. Additionally, there are ideas of resurrection which are central to the temple society religion of the Egyptians, long, long before the writing of the Torah. Despite claims to the contrary by christians, often displaying a marvelous and convenient ignorance, the "old testament" very likely was compiled from fragmentary sources after the Babylonian captivity. It is by no means certain that the original versions of Genesis were written
before Kings, Judges and Samuel. Those last six named books probably constitute the earliest portions of the "old testament" which were written down. There is sufficient contradiction in the descriptions of the deity to suggest, however, that many of the books which precede Kings, Judges and Samuel were at least oral traditions long before. The bible frequently demonstrates that monotheism was not a Hebrew idea until at least the time of the Babylonian captivity, if not later. The progression was more or less, "the god we prefer," "the supreme god" (the idea they got from the Persians), "the only true god"--and finally arriving at "the one god."
Despite the self-serving version of history promulgated by the Jews, the Hebrew tribes in Palestine before the Babylonian captivity were very likely illiterate Semites with no written traditions. Aramaic was the the lingua-franca of the middle east in those days, the Aramaens being a Semitic speaking people who excelled in commerce, and not only subsisted peacefully among their war-like neighbors the Assyrians and the Akkadians, but even worked diligently to create a commerical empire without reference to politics or military conquest. They largely succeeded. During the Babylonia captivity, the Hebrew tribesmen would have been exposed to the ancient culture and myths of the Akkadians, and very likely derived the stories of Genesis from them, particularly from the Gilgamesh Epic. The reference to a world flood probably refers to the Black Sea--the Black and Caspian Seas were joined in a very large fresh-water basin which was created by the drainage from the retreating glaciers of the last period of glaciation. That event had probably driven to the south the tribes which overcame the Sumerian civilization, the first temple society in the middle east.
The Medes and Farsi (i.e., the Persians) were Aryan tribesmen who began to migrate into the eastern portion of the middle east between 4,000 and 3,000 years ago. A priest named Zarathustra (in Greek, Zoaraster) who lived long before the writing of the "new testament" is credited with being the seminal influence for the monotheism of Judaism, Chrisitanity and Islam. You can find information on Zarathustra at
the Religious Tolerance website. First the Medes, and then the Farsi/Persians overran the Assyrians and the Chaldeans, and finally the Egyptians. Their version of Zoarastrianism held that all gods were simply evil spirits, except for their one, true god. As a reasonable estimate places the life of Zarathustra at about 1000 to 600 BCE, he certainly does predate the "new testament."
I don't think i need to add to what AU has just written, apart from underlining what he says by pointing out that the "Jesus cult" in christianity has only arisen within the last 150 years. It simply did not exist before the revivalism of England and the United States in the early and mid-19th century.