To do what the people demanded, Aaron took all their gold earrings and melted them to fashion a calf and the people claimed that this was the god that brought them out of Egypt. They took all the credit away from the living God and gave it to an image that was made by a man which could neither hear nor speak.
We may read this and think how ridiculous it was for them to forget what God did for them and turn to worship idols. We may never worship a golden calf, but how many times has God done a miraculous thing for us and as soon as trouble comes, we forget what He did. We must never doubt God's ability to help in any situation. He loves us too and just as He provided for Israel on their journey through the desert, He will provide for us.