Matthew 17:2

μετεμορφώθη, transfiguratus est, Vulgate; became altered in appearance. Such transformation in exalted states of mind is predicated of others, e.g., of Iamblichus (Eunapius in I. Vitâ. 22, cited by Elsner), and of Adam when naming the beasts (Fabricius, Cod. Pseud. V. T., p. 10). ἔμπροσθεν αὐτῶν, so as to be visible to them, vide Matthew 6:1. Luke's narrative seems to imply that the three disciples were asleep at the beginning of the scene, but wakened up before its close. καὶ ἔλαμψε … φῶς : these words describe the aspect of the transformed person; face sun-bright, raiment pure white.