The common theme of today’s readings is metamorphosis or transformation. The readings invite us to cooperate with the grace of God with the assistance of the Holy Spirit to transform our lives, by renewing them during Lent and to radiate the grace of the transfigured Lord around us by our Spirit-filled lives.
In today’s Gospel, Jesus is revealed in His Heavenly glory, superior to Moses and Elijah. The primary purpose of Jesus’ Transfiguration was to allow him to consult his Heavenly Father and ascertain His plan for His Son’s suffering, death and Resurrection. God’s secondary aim was to make Jesus’ chosen disciples aware of Jesus’ Divine glory, so that they might discard their worldly ambitions and dreams of a conquering political Messiah and might be strengthened in their time of trial. On the mountain, Jesus is identified by the Heavenly Voice as the Son of God. Thus, the transfiguration narrative is a Christophany, that is, a manifestation or revelation of  who Jesus really is. Describing Jesus’ Transfiguration, the Gospel gives us a glimpse of the Heavenly glory awaiting those who do God’s will by putting their trusting Faith in Him. Jesus’ transfiguration also strengthens us in the face of our afflictions.
In moments of doubt and during our dark moments of despair and hopelessness, the thought of our future transformation in Heaven will help us to reach out to God and to listen to His consoling words: "This is my beloved son." Let us offer our Lenten sacrifices to our Lord so that, through these practices of Lent and through the acceptance of our daily crosses, we may grow closer to him in his suffering, may share in the carrying of his cross and finally may share the glory of his second “transfiguration,” namely, his Resurrection.

Excerpt from Homilies of Fr. Anthony Kadavil on Mark 9:-2-10 available at http://stjohngrandbay.org