The following is from St. Michael's Center for the Blessed Virgin Mary
The Feast of Transfiguration is observed on August 6. This foretells the glory of the Lord as God, and His Ascension into heaven. It anticipates the glory of heaven, where we shall see God face to face. Through grace, we already share in the divine promise of eternal life. As we celebrate the Feast of the Transfiguration we are reminded on Christ who was beginning to teach his disciples that He must die and rise again. Jesus revealed Himself in shining splendor to Peter, James and John. Moses and Elijah were present and are taken to signify that the Law and the Prophets testify Jesus is the promised Messiah. During this glorious event, God the Father also proclaimed Jesus as such by saying, “This is my Beloved Son. Listen to him."Prayer
The purpose of the Transfiguration was to encourage and strengthen the Apostles who were depressed by their Master's prediction of His own Passion and Death. The Apostles were made to understand that His redeeming work has two phases: The Cross, and glory—that we shall be glorified with Him only if we first suffer with Him. Hence, the Feast of Transfiguration has a profound and sublime lesson for all times, and for Christians of all sorts and conditions. In this earthly life we must not expect every hour to offer us joy, pleasures and glory, even if we seek these with an honest and legitimate purpose.
God our Father, in the transfigured glory of Christ your Son, you strengthen our faith by confirming the witness of your prophets, and show us the splendor of your beloved sons and daughters. As we listen to the voice of your Son, help us to become heirs to eternal life with him who lives and reigns with you and the Holy Spirit, one God, for ever and ever. Amen