Peter Chrysologus — on Exod 13:21 (SERMON 170)

“At one time he appears all aglow in a bush. For you are cold with the perfidy of infidelity, and he wants to enkindle you with the heat of faith. At another time he glows like fire in a pillar extending toward heaven, that the darkness of your ignorance may be removed and that you can follow the way of saving knowledge through the wilderness of this world. At yet another time he is changed for you into a pillar of cloud, in order to restrain the burning ebullience of your passions.”