The Transfiguration: the Three Apostles.
I. What was our Saviour's purpose in making the three Apostles His witnesses? There were trials to which the Apostles would be subjected, and against them they wanted strength and a support for their faith. The Transfiguration was to give them this support. There they should see how the glory of the Lord shone forth from under the veil of His humanity; how life in the Resurrection triumphed over death; how joy and rest in the Lord, such as Moses and Elias enjoyed in this vision, surpassed all worldly pleasure and atoned for all earthly pain. This help to faith is free from the notion of a reward. It Was not the sight of a future reward that was held out to them upon the mount, but the sight of the present truth.
II. Consider the conduct of the Apostles. Of them it may be said that at the time they hardly comprehended what they saw, but that in after-life they felt its influence. At the time they were dazed and confused, like men just fallen into heavy sleep and then awaking to a strange sight. They darkly comprehended the Lord's purpose in taking them up with Him if they imagined they were to remain on the mount. Prayer has its luxury. Though it be hard to pray, it is sometimes at the end as hard to leave off praying. The peace of meditation has such a charm to soothe the unquiet mind, and to quell the unruly passions of the heart. To all who are thus inclined to God a voice will soon be heard to speak into the ear, "Descende, Petre; ora et labora" pray and work. The life which the Apostles experienced after that wonderful night upon the mountain with Christ was the same sort of life into which Christians pass out of their quiet chamber into the business of the day, out of the aisles of the church on Sunday into the work of the world on Monday.
C. W. Furse, Sermons at Richmond,p. 198.
Reference: 2 Peter 1:19. Good Words,vol. vi., p. 101.