164. And Isaiah shows that the Holy Spirit is not only Light but also Fire, saying: “And the light of Israel shall be for a fire.” So the prophets called Him a burning Fire, because in those three points we see more intensely the majesty of the Godhead; since to sanctify is of the Godhead, to illuminate is the property of fire and light, and the Godhead is wont to be pointed out or seen in the appearance of fire: “For our God is a consuming Fire,” as Moses said.