זוהר שמות — דף קצב ע”ב

Aaron took the gold from their hands and cast it into the fire, and the form of a bull emerged. Aaron saw that the impure side had strengthened and instituted a day of offering to sanctify that side and bind it to holiness. Scripture criticizes that Aaron took the gold from their hands and not from the ground — had he taken it from the ground, the magic could not have worked. Jeroboam learned from this sin and multiplied the calves in Dan. Jeroboam’s sin was grave because it severed the bond between Israel and their Father.