Joshua 24:2 "And Joshua said to all the people, “Thus says the Lord, the God of Israel, ‘Long ago, your fathers lived beyond the Euphrates, Terah, the father of Abraham and of Nahor; and they served other gods." (ESV; Emphasis mine)
Joshua 24:14-15 “Now therefore fear the Lord and serve him in sincerity and in faithfulness. Put away the gods that your fathers served beyond the River and in Egypt, and serve the Lord. 15 And if it is evil in your eyes to serve the Lord, choose this day whom you will serve, whether the gods your fathers served in the region beyond the River, or the gods of the Amorites in whose land you dwell. But as for me and my house, we will serve the Lord.” (ESV; Emphasis mine)
Joshua 24:2 shows that Abraham was involved in that idolatry. First off, he was 70 when God called him. Secondly, it was common in his day to have "territorial gods" for each city/state. It would have been quite common for Abraham to join in the worship of the local deity.
Further the text says "...and they served other gods." The simple sentence is "Your fathers lived beyond the Euphrates and they served other gods. The naming of the fathers--Terah, Abraham, and Nahor is periphrastic, identifying the fathers. The "they" encompasses all of the fathers including Abraham (since, after all, he is mentioned by name).
Had Joshua wanted to suggest that only Terah had been an idol worshiper, the sentence would have to be constructed quite differently--to emphasize only Terah, rather than the all the fathers which includes Abraham.
Blessings,
The Archangel
I don't know if I agree with you here, it is simply identifying who Terah is, the father of Abraham and the son of Nahor. The Jews and even the Muslims deny that Abraham was an idolator, but concede his father was.
According to the midrash, Genesis Rabba, a Palestinian midrash written sometime in the 5th or 6th century of the common era, Abraham’s father, Terach, was an idolator and an idol maker. One day he left Abraham in charge of his idol store. As each person came to buy an idol, Abraham would make fun of them. When an old person came to buy an idol, Abraham looked at him incredulously and said: “Why would you worship an idol that was made just yesterday?”
Later that day, a woman came to the store with an offering of grain to give to the idols. Abraham took a mallet and smashed all the idols save the largest one. When Terach returned he was understandably furious.
“What happened here?”
Abraham calmly explained that there was a fight over the offering that was brought to the idols and the largest idol smashed all the other idols. Terach was beside himself.
“These idols can’t move, let alone fight with each other!!”
“If that’s the case,” Abraham replied, “why would you worship something that cannot do anything?”
Terach dragged Abraham to the king, Nimrod. Nimrod and Abraham engaged in a type of religious disputation. Nimrod opened with: “I worship fire.” Abraham countered with: “Why don’t you worship the water which can douse the fire.” Nimrod acquiesced. “Okay, I’ll worship the water.” “So then,” Abraham went on, “you might as well worship the clouds, since they are obviously stronger than the water which they carry.” Nimrod agreed with this and said: “Okay, let us worship the clouds.” Abraham then suggested the wind which blows the clouds, and then, finally, a person who can withstand the wind.
Nimrod finally exploded at Abraham: “You are just playing with words. I worship the fire. When I throw you into the fire, we’ll see whether your god is greater than the fire, or whether you succumb to my god.”
Abraham was thrown into the fire and, like Shadrach, Mishach, and Abednego in the time of Daniel, Abraham emerged unscathed.
This midrash, significantly, is a commentary to the last verse before God issues those famous marching orders: lech lechah, go forth! Read in this light, the midrash seems to be arguing that before Abraham could move on to the “land that I will show you,” he had to smash his father’s idols.
Rabbi Yakov Yosef of Polnoi, one of the two main students of the founder of Hassidism, the Ba’al Shem Tov, would often start his weekly discourse with the following question: How is this part of the Torah relevant in every time and every place? In other words, how does my life hang in the balance over whether Abraham smashes the idols or not? Or, from another perspective, what are the idols that I have to smash in order to move on to the Promised Land? (and, perhaps, then, what is that promised land?)