Moses has been called into the presence of God to receive the law. While Moses is with God, what are the people doing?

"Now when the people saw that Moses delayed coming down from the mountain, the people gathered together to Aaron, and said to him, 'Come, make us gods that shall go before us; for as for this Moses, the man who brought us up out of the land of Egypt, we do not know what has become of him.'" {Exodus 32:1}

What problem do these people have? It seems they cannot follow God unless someone is leading them and reminding them what to do! God, and Moses are out of sight, so they demand new leadership. Like the old saying, "out of sight, out of mind."

What is the reply of Aaron? This was the brother who was given to Moses as a spokesperson for his brother. "And Aaron said to them, 'Break off the golden earrings which are in the ears of your wives, your sons, and your daughters, and bring them to me.' So all the people broke off the golden earrings which were in their ears, and brought them to Aaron. And he received the gold from their hand, and he fashioned it with an engraving tool, and made a molded calf. Then they said, This is your god, O Israel, that brought you out of the land of Egypt." {Exodus 32:2-4}

How could he do such a thing? God had strictly forbidden that they bow down to any graven image, Exodus 20:3-5. He was leading them into a grievous sin.

God instructed Moses to go down because His people "corrupted themselves," Exodus 32:7. He told Moses they were now worshipping and offering sacrifices to a golden calf!

Of course Moses goes to Aaron and wants to know why he has done this thing. "...Do not let the anger of my lord become hot. You know the people, that they are set on evil...Whoever has any gold, let them break it off.' So they gave it to me, and I cast it into the fire, and this calf came out."{Exodus 32:22,24}

Aaron tried to place his part on God's people. Notice, the "calf just came out." No it was molded and Aaron had molded it! 3,000 men lost their lives in that day because of this great sin.