Father Gabriel of St Mary Magdalen, O.C.D.
The soul of Jesus, personally united to the Eternal Word (cf., Jn 1.1), enjoyed the Beatific Vision, which has as its connatural effect the glorification of the body. But this effect was impeded by Jesus Himself, who during the years of His life on earth, wanted to resemble us as much as possible by appearing “in the likeness of sinful flesh” (Rom 8.3). However, in order to confirm the faith of the Apostles who were shaken by the announcement of the Passion, Jesus permitted some rays from His blessed soul to shine forth for a few brief instants on Thabor, when the Apostles saw Him transfigured. The three were enraptured by it, and yet Jesus had revealed to them only one ray of His glory, for no human creature could have borne the complete vision here on earth.
Glory is the fruit of grace: the grace possessed by Jesus in an infinite degree is reflected in an infinite glory transfiguring Him entirely. Something similar happens to us: grace will transform us from glory to glory (2 Cor 3.18), until one day it will bring us to the Beatific Vision of God in heaven. But while grace transfigures, sin, on the other hand, darkens and disfigures whoever becomes its victim.
The Divine Master teaches His disciples in this way that it was impossible – for Him as well as for them – to reach the glory of the Transfiguration without passing through suffering. It was the same lesson that He would give later to the two disciples at Emmaus: Ought not Christ to have suffered these things and so to enter into His glory? (Lk 24.26). What has been disfigured by sin cannot regain its original supernatural beauty except by way of purifying suffering.