Bible Answer

Did Jews practice Pagan worship after Babylon?

After the Jews returned from Babylon, they no longer participated in idol worship. But didn't the Hellenistic Jews invent paganism? Mattathias the Hasmonean killed a Hellenistic Jew who stepped forward to offer a sacrifice to an idol, and this was long since their return from Babylon.

You cited the example of the Maccabean revolt when Mattathias struck down the Jew who participated in Greek pagan worship practices as evidence that the Jews practiced pagan worship after the Babylonian captivity, but this example is actually proof of the opposite conclusion. Following the Babylonian captivity, the Jewish people never again embraced pagan worship. While there have always been some in Israel who followed after pagan practices (even as there are today), the nation as a whole did not embrace pagan worship again. Instead, the nation remained devoted to the Law of the covenant and to the God of Israel – apart from a few apostate Jews. 

Indeed, whenever the nation was forced by an oppressor to adopt pagan practices, it inevitably led to Jewish protest and an armed uprising (e.g., the Maccabean revolt, the Jewish-Roman War, & the Bar Kohkaba Revolt). This was a dramatic change from the years prior to captivity in Babylon, when the Jewish nation would wholeheartedly embrace pagan practices even to the point of forgetting that the Law of Moses even existed! (See 2 Kings 22:8-20).