The Israelites don't keep the faith
This transformation from polytheism to worshipping a single god was carved in stone, literally. For example, an inscription in a tomb in Khirbet Beit Lei, near the Judahite stronghold of Lachish, states that “Yhwh is the god of the whole country; the mountains of Judah belong to the god of Jerusalem.”
Josiah’s reforms were also enshrined in the book of Deuteronomy – whose original version is thought to have been compiled around this time – and especially in the words of Deut. 6, which would later form the Sh’ma Yisrael, one of the central prayers of Judaism: “Hear, O Israel, Yhwh is our God, Yhwh is one.”
But while Yhwh had, by the dawn of the 6th century BCE, become “our” national god, he was still believed to be just one of many celestial beings, each protecting his own people and territory.
This is reflected in the many biblical texts exhorting the Israelites not to follow other gods, a tacit acknowledgement of the existence of those deities, Romer explains.
For example, in Judges 11:24, Jephtah tries to resolve a territorial dispute by telling the Ammonites that the land of Israel had been given to the Israelites by Yhwh, while their lands had been given to them by their god Chemosh ("Will you not take what your god Chemosh gives you? Likewise, whatever Yhwh our god has given us, we will possess.")
The Sun Carriage, a religious artifact of sun worship dating from the Bronze Age: Did the birthdate chosen for Jesus coincide with that of the sun god? Malene Thyssen, Wikimedia Commons
Snatching God from the jaws of defeat
The real conceptual revolution probably only occurred after the Babylonians' conquest of Judah and arson of the First Temple in 587 B.C.E. The destruction and the subsequent exile to Babylon of the Judahite elites inevitably cast doubts on the faith they had put in Yhwh.
“The question was: how can we explain what happened?” Römer says. If the defeated Israelites had simply accepted that the Babylonian gods had proven they were stronger than the god of the Jews, history would have been very different.
But somehow, someone came up with a different, unprecedented explanation. “The idea was that the destruction happened because the kings did not obey the law of god,” Römer says. “It’s a paradoxical reading of the story: the vanquished in a way is saying that his god is the vanquisher. It’s quite a clever idea.
“The Israelites/Judahites took over the idea of the divine wrath that can provoke a national disaster but they combined it with the idea that Yhwh in his wrath made the Babylonians destroy Judah and Jerusalem,” he said.
The concept that Yhwh had pulled the Babylonians' strings, causing them to punish the Israelites inevitably led to the belief that he was not just the god of one people, but a universal deity who exercises power over all of creation.
This idea is already present in the book of Isaiah, thought to be one of the earliest biblical texts, composed during or immediately after the Exile. This is also how the Jews became the “chosen people” – because the Biblical editors had to explain why Israel had a privileged relationship with Yhwh even though he was no longer a national deity, but the one true God.
Over the centuries, as the Bible was redacted, this narrative was refined and strengthened, creating the basis for a universal religion – one that could continue to exist even without being tied to a specific territory or temple. And thus Judaism as we know it was established, and, ultimately, all other major monotheistic religions were as well.