זוהר שמות — דף קעג ע”ב

The verse says his angels are winds and his ministers a flaming fire, showing that the outer angels are wind and the inner ministers are fire. The spirit of impurity and the spirit of holiness do not mix, and the inner fire repels impurity. The three watches of the night correspond to the three camps of praise. The lamp of David, Master of all, never goes out but constantly gives thanks and praise. At midnight the north wind stirs and evil spirits retreat to the abyss; Rabbi Elazar and Rabbi Abba rose to study Torah.