Exodus 32

Exo 32:19 When Moses came close enough to the camp to see the bull-calf and to see the people dancing, he became furious. There at the foot of the mountain, he threw down the tablets he was carrying and broke them.
Exo 32:20 He took the bull-calf which they had made, melted it, ground it into fine powder, and mixed it with water. Then he made the people of Israel drink it.

The Israelites thought that Moses was gone. They thought that he would not come down again from Mount Sinai. With Moses gone (so they thought) the Israelites began to be restless. They asked Aaron to make a golden calf that they can worship, a god that will replace the God of Moses, a god they can manipulate.

When Moses and Joshua heard the noise, they thought that the Israelites were in battle. But Moses knew that it’s not the sound of battle but a sound of celebration for the Lord spoke to Moses and told him what was happening in the Israelite camp. When they returned, they found the Israelites celebrating, feasting and worshipping an idol.

In anger the Lord meant to destroy the Israelites but Moses pleaded on their behalf.