The Doctrine of Christ - Transfiguration of Christ

"For we have not followed cunningly devised fables, when we made known unto you the power and coming of our Lord Jesus Christ, but were eyewitnesses of His majesty." (2 Peter 1:16)
In Matthew 17, Jesus was temporarily glorified in the presence of three disciples. This was a foreshadowing of Christ's coming in power and glory to establish His kingdom. The presence of Moses and Elijah on the mountain represented all those who enter the kingdom by death or translation (while also representing The Law and The Prophets which point to Christ). The declaration of the Father reinforces Christ's dominion over His kingdom.
Application: Since Christians live expectantly looking forward to the return of Christ, they ought to give Him first place in their lives today, just as He will have in the kingdom.