Forbidden Worship

It is precisely the attempt to worship Yahweh by means he has already declared totally unacceptable that makes the sin of the golden calf so destructive, far more so than a simple shift of allegiance to "other" or "foreign" gods. The people receive the calf with the confession "These are your gods, Israel, who brought you up from the land of Egypt," an act they had attributed to Moses, albeit certainly as Yahweh's representative, in [Exodus 32:1]. And Aaron, in obvious and and specific response, declares a sacred day to Yahweh, not to the calf, or to any other god or gods. The composite of Exod 32:1-6 is not an account of the abandonment of Yahweh for other gods; it is an account of the transfer of the center of authority of faith in Yahweh from Moses and the laws and symbols he has announced to a golden calf without laws and without any symbols beyond itself. Moses is the representative of a God invisible in mystery. The calf is to be the representative of that same God, whose invisibility and mystery is compromised by an image he has forbidden.

--John I. Durham, Exodus (Word Biblical Commentary 3; Dallas: Word, 1987), 421-422.