He follows, on his departure, Him who calls, as quickly, so to speak, as He who goes before calls, hasting by reason of a good conscience to give thanks; and having got there with Christ, shows himself worthy, through his purity, to possess, by a process of blending, the power of God communicated by Christ. For he does not wish to be warm by participation in heat, or luminous by participation in flame, but to be wholly light.