In the sin of the Golden Calf, “they got up to revel” as a result of the convergence of both factors: lowering the exalted and exalting the low.
We are constantly beset with base drives, whether it is the drive to engage in forbidden sexual relations or the drive to commit acts of violence, and we can usually keep these desires in check.
But the moment one invests a base drive with lofty meaning, it becomes, in one’s own mind, not only permissible but a mitzva.
Even if, ordinarily, one would be embarrassed to commit a certain act, once it is wrapped in a lofty mantle, that same act becomes exalted.
When the two factors converge, the idolatry appears in its full force, to the point of “they got up to revel.”
This calf was not Aaron’s calf; it was a calf produced by the people, by the lowest individuals of Israel, and elevated to a position of holiness.
Rabbi Adin Steinsaltz