זוהר שמות — דף קפה ע”ב

All the other sides below are more impure, and the lower they descend in degrees the greater their impurity. In the goat, the share of the other side is greater because it belongs to that side. The figure of the goat is that of the scapegoat of Yom Kippur. There is a deep secret: the other side must receive its portion so that it remains silent and does not disturb Israel. But the secret of all is the secret of the supernal unity.