זוהר שמות — דף קצא ע”ב

The erev rav consisted of Egyptian sorcerers who practiced magic at sunset. They were called erev rav because Israel relied upon them. Aaron had good intentions but many Israelites had joined them in their hearts. Moses was required to purify the people by making them drink water mixed with the powdered calf, and the Holy One blessed be He ultimately forgave Israel. The sin of the golden calf is thus analyzed in its inner and outer dimensions.