After God had spoken the Ten Commandments to all the people, and they had agreed to obey everything, Moses went to the top of the mountain to talk to God. God made two stone tablets, and, with his own finger, carved the Ten Commandments onto the tablets. Moses was on the mountain for forty days.
When the people saw that Moses was so long in coming down from the mountain, they gathered around Aaron and said, "Come, make us gods who will go before us. As for this fellow Moses who brought us up out of Egypt, we don't know what has happened to him." So all the people took off their earrings and brought them to Aaron. He took them and made an idol cast in the shape of a calf. Then they said, "These are your gods, O Israel, who brought you up out of Egypt." Then they began to sing and dance and worship that golden calf.
On top of the mountain, God had finished writing the Ten Commandments, and He said to Moses, “The people have already turned away from me. Now leave me alone so that I may destroy them!” But Moses pleaded with God to remember his covenant with Abraham, Isaac, and Jacob, and to not destroy His people.
So Moses went down the mountain. When he saw the people singing and dancing and worshiping the golden calf, he was very angry. Moses threw down the stone tablets, and they broke into pieces. Then he called with a loud voice, “If anyone worships the true God, come to me!” Out of the twelve tribes of Israel, only the tribe of Levi came to him. Moses told them, “Each one of you take your sword and kill those worshiping the golden calf!” Many people died that day, and the rest of Israel repented of their sin.
Because he had broken the stone tablets, Moses went back up the mountain to God. And God made Moses to carve out more tablets of stone, and he put the Ten Commandments onto them. These were the tablets that Moses put into the Ark of the Covenant.
After many days at Mt. Sinai, God led Israel toward the Promised Land.