Even as Moses is up on Sinai receiving instructions for how the people are to worship God, Israel begins the construction of and worship of an idol. As the Psalmist says in Psalm 106
They exchanged their Glory, for an image of a bull, which eats grass.
They forgot the God who saved them, who had done great things in Egypt,
miracles in the land of Ham and awesome deeds by the Red Sea.
Just like Israel in moments of uncertainty our faith can get wobbly and we can so easily fall back into worshipping the old gods we thought we had left behind.
Cambridge: Exodus