Avodah zarah—idolatry עבודה זרה

"You shall have no other gods before Me"—the second of the ten utterances, and this prohibition is one of the three for which a man is commanded to give up his life rather than transgress.

How it began. Rambam, at the opening of the Laws of Idolatry, tells it as a corruption, not an invention: in the days of Enosh men reasoned that since God had set the heavenly lights to serve the world, honour was due to them too—and they began to honour the lights for His sake. Generations later the beginning was forgotten, and only the images remained. The explanation matters: idolatry here is not a savage's folly but a reasonable thought that took one step aside.

Why it would not end. Reading the books of Kings, one sees the idols come back under every second king, and the rooting out has to be done again and again—Asa, Jehoshaphat, Hezekiah, Josiah. The reason is simple: the neighbours' gods promised rain and harvest and demanded little; the service of the Holy One demanded a whole way of life. It was not a theological error but a convenience.

And why it did end. After the return from Babylon idolatry disappears in Israel, and the sages say so plainly: the men of the Great Assembly prayed that the craving for it be taken away. Since then the tractate Avodah Zarah is not about the temptation of one's own people but about how to live beside another's worship: trade, wine, the neighbours' festivals.