For many years I have wondered why the Hebrews chose a calf as the idol to worship during the Exodus. Where did they get such an idea? The root of this question lands in our laps, "How do we choose our idols?"
I found an excellent article on-line that I believe answers the question:
John N. Oswalt, “The Golden Calves and the Egyptian Concept of Deity,” Evangelical Quarterly 45.1, (January-March 1973): 13-20
As you can see the article is rather lengthy so if you wish you may go here to read it in its entirety. Otherwise, I paraphrase.
Around the time of the Exodus, Egypt was leading towards monotheism. Their one god was Amon-Re. Like Yahweh/Jehovah, Amon-Re was all powerful, creator, good, and merciful. But unlike our God, the Egyptian god had a likeness, that of a bull. This signified his all-powerful/creator status, that is, his sexual prowess.
This is the culture in which the Hebrews were born, raised, worked, lived, and died. By the time they left Egypt, most had forgotten the God of Abraham. In fact, until Moses, none had any encounters with Him at all. Therefore, Amon-Re was foremost in their minds.
When Aaron constructed the golden calf however, he did not construct an image of Amon-Re. No, the knowledge of what Yahweh/Jehovah God had just done was too fresh and too powerful. The Hebrews could not deny what their eyes beheld during the Egyptian plagues, the Passover, the Red Sea, and now the firey, smoking mountain where Moses was. The Hebrews had certainly come to know again the God of Abraham as their God.
But in the hardness of their hearts they fell back on what they knew, not who they knew, as their god to worship. They saw the great power, the miracles, the deliverance. So they reverted to what was so powerfully portrayed in their minds as the image of who was responsible for all this. They drew a parallel and concluded that this calf was not really Amon-Re, it was Yahweh/Jehovah God Himself!
And this is why Moses was so upset when he came down and saw them worshiping the idol. It was not just because of the fact that it was an idol of Amon-Re, not because of the lewd sexual acts performed in prostrate worship of the idol. No, what upset Moses the most was that the Hebrews called this idol God. The calf represented both the visible and invisible (g)Gods that they knew.
Fast forward a few more centuries to another meeting with Jesus and the Samaratin woman at the well in John 4:20-24.
(The woman said), "Our fathers worshipped in this mountain; and ye say, that in Jerusalem is the place where men ought to worship. Jesus saith unto her, Woman, believe me, the hour cometh, when ye shall neither in this mountain, nor yet at Jerusalem, worship the Father. Ye worship ye know not what: we know what we worship: for salvation is of the Jews. But the hour cometh, and now is, when the true worshippers shall worship the Father in spirit and in truth: for the Father seeketh such to worship him. God is a Spirit: and they that worship him must worship him in spirit and in truth."
Notice again the tendency towards the seen and familiar versus the unseen yet familiar.
We idolize what is known and seen and familiar. We derive these idols from our culture, our upbringing, our education.
God is not known because He is seen or familiar or culturally popular or part of our Christian homes or education. He is only known of those whom He knows and chooses and saves by the quickening of the spirit. Hence we can worship Him alone in spirit and in truth.
This is why God warned Moses and Joshua to rid the land of all the idols and the places of worship. Remove the pictures. Destroy the remnants of culture. Give no opportunity to the flesh. Thou shalt have no other gods before me.