When the people saw that Moses delayed to come down from the mountain, the people gathered around Aaron, and said to him, "Come, make gods for us, who shall go before us; 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."
Aaron said to them, "Take off the gold rings that are on the ears of your wives, your sons, and your daughters, and bring them to me."
So all the people took off the gold rings from their ears, and brought them to Aaron.
He took the gold from them, formed it in a mold, and cast an image of a calf; and they said, "These are your gods, O Israel, who brought you up out of the land of Egypt!"
References for Exodus 32:4
When Aaron saw this, he built an altar before it; and Aaron made proclamation and said, "Tomorrow shall be a festival to the Lord."
They rose early the next day, and offered burnt offerings and brought sacrifices of well-being; and the people sat down to eat and drink, and rose up to revel.