998 B
made a golden idol
Aaron took the things made of gold that the people had brought to him, melted them, combined them, and formed them into the shape of a calf.
The people began to wildly worship the idol and make sacrifices to it!
This is a strong statement that expresses how shocking it was that the people would worship this idol when they had seen what God had done for them. (See: rc://en/ta/man/translate/figs-exclamations)
to wildly worship
The people were sinning by worshiping the idol and also by doing sinful things as they worshiped it.
because
God had just told the Israelites that they were only to worship him because he was a jealous God, and if they did not obey they would be punished. For these reasons, God was very angry with the Israelites because of their sin. (See: rc://en/ta/man/translate/grammar-connect-logic-result)
listened to his prayer
God always hears prayer. In this situation, listened means that God agreed to do what Moses asked.