Let us consider the transfiguration not only as it relates to the work of the mediator, but in reference to what Christ intended to achieve by it.
To Show His Disciples a Glimpse of His Glory in Heaven
Christ intended to show His disciples a glimpse of His glory in heaven, and particularly the glory of His person in his coming the second time to judgment. Prior to this He had promised that they would see His glory before they tasted death.
The glory of Christ at His second coming shall be great. “He shall come in the glory of His Father.” Not only will He be glorious in regard of His train and His throne, but in His person.
Theologians give some reasons for this transcendent glory. One is because His coming to judgment is the height of His exaltation. That’s why it says in the Creed, “… from thence shall He come to judge …” as the last step of His exaltation. The highest step of His exaltation must be full of glory.
Another reason is that it is fitting that those by whom He was despised and rejected should see Him as eminently glorious. At the Great Day that they are most afraid of His face. “Fall on us, and hide us from the face of the Lamb,” is their cry to the hills and mountains — not so much to be hidden from hell, as from His face.
The third reason is for the comfort of His people. They have forsaken all for Him, and the wisdom of their choice will be commended (in the judgment of their enemies) by this, when He shall appear in the brightness of His Father’s glory.
All this should stir us up to look on Christ as one who is in transcendent glory now (as well as that He will be seen to be so at His second coming). This is advantageous in several ways.
It guards us against stumbling when we encounter all the ignominious reproaches that attend us when we follow Him here. He was, and His followers still are, a sight for passers-by to wag their heads at. Yet, above, He is the temple, the light, and the admiration of all who behold Him.
It allows us to discern that not only our nature but our persons are advanced in Him as the second Adam, and the one head of all believers. By Him they are all represented. However despicable they may be in themselves, yet they are glorious in Him.
It reminds us to be humble. Though we are warranted to come with boldness to His throne of grace, yet still we are to remember His glory, and what a vast inequality there is between us and Him, seeing we are base and polluted, and He is the glorious Lord.
It will make us love and long for Him to come. Though many still cast His cords from them and despise His yoke, yet He shall then be exalted even by His enemies, who shall tremble at the sight of His transcendent glory.
To Give His Disciples a View of the Glory of the Saints’ Bodies
The second aim which Christ had in mind in the transfiguration was to give us a view of the glory which the bodies of His saints (who will be conformed to His image) shall have in heaven from His transfiguration. Not only shall their souls partake of excellent glory, but their bodies shall be changed, and made like His glorious body.