The People Descend Into Idolatry
With Moses gone for almost a month and a half, the people quickly became disoriented and asked Aaron to give them another god-symbol to lead them. Interestingly, they still seem to have viewed this idol as a representation of the Eternal (verses 4-5). God, however, saw it otherwise, saying that they "worshiped it and sacrificed to it" (verse 8) rather than "to Me." With all God had done for them, it is amazing how quickly they forgot His commands—and dismissed Moses as if he were a fraud. The apostle Paul even warns us to learn from what they did and not do the same thing (1 Corinthians 10).
Another incredible aspect of this whole affair is Aaron's part. It seems almost stupefying that he would consent to it—and seemingly so readily. When the people approached Aaron with the suggestion to make an idol that they could worship, it was he who told them to give him their golden earrings. It was then Aaron who formed and shaped the idolatrous object. Perhaps Aaron himself had begun to wonder what had become of Moses. It is likely that he viewed the people's "request" as an implicit threat—which it probably was—that if he didn't go along with what they wanted, the consequences would be dire. Aaron likely feared for his own safety and that of his family if he opposed the movement underway. He should have shown more stamina and trust in God, but he went along. To top it off, rather than face up to his responsibility, he told Moses a ridiculous lie (verse 24). In any case, there was certainly a failure of leadership at a high level. This too should be a lesson for all of us. No matter who we are, no matter how much we have seen God do in our lives, we can be led astray if we aren't constantly on guard spiritually.
Concerning the Israelites' chosen object of idolatry, they were well acquainted with Egyptian calf worship, detailed in the discussion of the plagues. It's not surprising that they would choose a calf as a symbol of their worship, because it was common in the Egyptian culture in which they had been immersed for many generations. Centuries later the Israelite king Jereboam would fashion similar idols (1 Kings 12:28 1 Kings 12:28Whereupon the king took counsel, and made two calves of gold, and said to them, It is too much for you to go up to Jerusalem: behold your gods, O Israel, which brought you up out of the land of Egypt.
American King James Version×) after being banished to Egypt (1 Kings 11:40 1 Kings 11:40Solomon sought therefore to kill Jeroboam. And Jeroboam arose, and fled into Egypt, to Shishak king of Egypt, and was in Egypt until the death of Solomon.
American King James Version×), and this idolatrous worship would remain prevalent throughout most of the time of the northern kingdom of Israel. Among the Canaanites, the bull was also seen as an embodiment of Baal. Perhaps the widespread worship of oxen in paganism, as in India today, has been directly inspired by Satan, as his main face—him being a cherub—is that of an ox (compare Ezekiel 10:14 Ezekiel 10:14And every one had four faces: the first face was the face of a cherub, and the second face was the face of a man, and the third the face of a lion, and the fourth the face of an eagle.
American King James Version×; Exodus 1:7-10 Exodus 1:7-10  And the children of Israel were fruitful, and increased abundantly, and multiplied, and waxed exceeding mighty; and the land was filled with them.  Now there arose up a new king over Egypt, which knew not Joseph.  And he said to his people, Behold, the people of the children of Israel are more and mightier than we:  Come on, let us deal wisely with them; lest they multiply, and it come to pass, that, when there falls out any war, they join also to our enemies, and fight against us, and so get them up out of the land.
American King James Version×).
"The bull was revered throughout the ancient Near East as the symbol of fertility" (Jonathan Kirsch, Moses: A Life, 1998, p. 264). It may have been the fertility connection involved in this idolatrous worship that stimulated some of the Israelities to become involved in sexual "play" (verse 6). The Expositor's Bible Commentary has this to say about verse 6: "The verb sahaq signifies drunken, immoral orgies and sexual play ('conjugal caresses')" (1990, Vol. 2, p. 478). In reaching this level, the unseemly episode had probably gone way beyond what Aaron had agreed to or perhaps even imagined. We read earlier that the apostle Paul compared sin to leavening (1 Corinthians 5:8 1 Corinthians 5:8Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.
American King James Version×). He even used an example to show that sin, like leaven, can spread to affect more and more people unless it is stopped in its tracks (verses 1-7). The incident with the golden calf seems like a classical case of allowing some leaven in and, as is the proclivity of leaven, before long the leaven had permeated insidiously. We need not necessarily think that the entire congregation of Israel had degenerated into extensive sexual immorality, but it was widespread enough that God told Moses, "Your people whom you have brought out of the land of Egypt have corrupted themselves" (verse 7)—effectively disassociating Himself from the Israelites.
Though God forgave Israel's sin—including that of Aaron—they paid a costly fee for such gross violation of God's law. Moses told the Levites to take their swords and begin to slay the people. About 3,000 were killed (verse 28). Those who were slain may have been among the ringleaders or those who pushed things to an extreme once the partying started. Verse 35 states that God plagued the people because of the golden calf incident. This may be a reference to the slaying of the 3,000, or it may refer to an additional, unspecified punishment. The lesson that rings loud and clear from all this is that sin exacts a penalty. There is no exception to this principle.