32:17,18
Joshua was with Moses, so had no part in the rebellion. When he heard the noise in the camp he thought there was a battle of some sort going on. This is an indication of the extent to which the people had let themselves go. It then became apparent that it was actually the sound of singing, the people were singing with great exuberance to this useless idol. People can commit themselves with great gusto to all sorts of evil and wrong ideas.
32:19,20
In 32:10 we read of the Lord’s wrath burning hot, now we read of Moses’ anger burning hot. Moses had a problem with anger, but his anger was not always misplaced. Anger is not always wrong, indeed there are many things that we are right to be angry about. Here Moses was angry that the people were rebelling against the Lord. So he understood something of the Lord’s anger. The problem with our anger is that even when it may start out as righteous anger, it can so easily become unrighteous anger. This could be seen as symbolic, though I think it is more likely that Moses did it in a fit of rage. Of course, there may have been a mixture of the two. He then destroyed the calf, burning it down and grinding it to powder. Then he made the people drink water with the remains of the calf in it.