Will you explain Exodus 32:30 to me?
"On the next day Moses said to the people, "You yourselves have committed a great sin; and now I am going up to the LORD, perhaps I can make atonement for your sin"" (Exodus 32:30).
Israel had broken the first two commandments God had given them (Exodus 20:3-4) while Moses was up on Mt. Sinai getting a written copy of those very laws. So Moses returned to Mt. Sinai to talk to God. "Then Moses returned to the LORD, and said, "Alas, this people has committed a great sin, and they have made a god of gold for themselves"" (Exodus 32:31).
Atonement means to repair the damage caused by a wrong done. It is trying to calm down the hostilities between two parties due to the misbehavior of one party. In this case, Moses understands that God has every right to be angry with Israel -- he is angry himself. But Moses hoped to repair the damage that Israel had caused to their relationship with God.
What he did was to ask God to forgive the people and if God couldn't forgive Israel, Moses asked that he join the people in not reaching heaven. "But now, if You will, forgive their sin -- and if not, please blot me out from Your book which You have written!" (Exodus 32:32). God turned down Moses' request because Moses did not understand that sin is a personal responsibility. "The LORD said to Moses, "Whoever has sinned against Me, I will blot him out of My book. But go now, lead the people where I told you. Behold, My angel shall go before you; nevertheless in the day when I punish, I will punish them for their sin." Then the LORD smote the people, because of what they did with the calf which Aaron had made" (Exodus 32:33-35).