Exodus 32:3 (KJV)

And when the people saw that Moses delayed to come down out of the mount, the people gathered themselves together unto Aaron, and said unto him, Up, make us gods, which shall go before us; for as for this Moses, the man that brought us up out of the land of Egypt, we wot not what is become of him.

And Aaron said unto them, Break off the golden earrings, which are in the ears of your wives, of your sons, and of your daughters, and bring them unto me.

And all the people brake off the golden earrings which were in their ears, and brought them unto Aaron.

And he received them at their hand, and fashioned it with a graving tool, after he had made it a molten calf: and they said, These be thy gods, O Israel, which brought thee up out of the land of Egypt.

And when Aaron saw it, he built an altar before it; and Aaron made proclamation, and said, To morrow is a feast to the Lord.