The Children of Israel’s creation of the Golden Calf must have been traumatic for Moses because he retells the story at length in Eikev.
First, Moses warns the people that it’s not because of their own merit that God will allow them to possess Eretz Israel. It’s because 1) the people they’re dislodging are wicked and 2) God made a promise to Abraham, Isaac and Jacob.
In fact, Moses reminds them: “You guys made God furious enough that God wanted to kill you all: I fasted for 40 days and forty nights – no food, no water — because I was in dread of God’s anger! God wanted to destroy you! I begged God: Don’t bring ruin on your people! How will it look to the Egyptians? They’ll say you weren’t able to bring your people to the Promised Land!”
After Moses’ fast, God told him to carve two more stone tablets and make a wooden box to hold them in. Then he was to go back up the mountain. There, God wrote on the tablets. Moses put them in the box and schlepped back down the mountain to his people. Remember, Moses was eighty years old at the time!
In Eikev, also, it’s casually mentioned that Aaron died. There’s no commentary or detail about such an important person: just his death.
Food for Thought
The Talmud Yerushalmi (Ta’anit 4:5) states: “There is no generation that doesn’t have at a least a particle of the sin of the golden calf.” What does that mean? Do you agree?