“…Our Lord, after foretelling His Passion to His disciples, had exhorted them to follow the path of His sufferings (Matthew 16:21-24). Now in order that anyone go straight along a road, he must have some knowledge of the end: thus an archer will not shoot the arrow straight unless he first see the target. Hence Thomas said (John 14:5): ‘Lord, we know not whither Thou goest; and how can we know the way?’ Above all is this necessary when hard and rough is the road, heavy the going, but delightful the end. Now by His Passion Christ achieved glory, not only of His soul, not only of His soul, which He had from the first moment of His conception, but also of His body; according to Luke (24:26): ‘Christ ought [Vulgate: ‘ought not Christ’] to have suffered these things, and so to enter into His glory (?).’ To which glory He brings those who follow the footsteps of His Passion, according to Acts 14:21: ‘Through many tribulations we must enter into the kingdom of God.’ Therefore it was fitting that He should show His disciples the glory of His clarity (which is to be transfigured), to which He will configure those who are His; according to Philippians 3:21: ‘(Who) will reform the body of our lowness configured [Douay: ‘made like’] to the body of His glory.’ Hence Bede says on Mark 8:39: ‘By His loving foresight He allowed them to taste for a short time the contemplation of eternal joy, so that they might bear persecution bravely.’” (St. Thomas Aquinas; Summa Theologiae, III.45.1)