The Transfiguration confirms what Jesus has said, that everything will be different, especially in the face of losing one we love. Finding ourselves in the middle of change, we may be afraid but we are not alone. We have Jesus to guide us, to bring life where there is death, wholeness where there is brokenness. The essence of Christianity is that we do not need to fear death; death is a change, not an ending. When we die our life in Christ goes on. In the resurrection life we do not lose ourselves, we become our true selves forever. We cannot stay on the mountain, but we can choose how we go down; transfigured, the glory of Christ alive in us.
The Scripture references are Exodus 24:12-18, Psalm 99:1,2,5-8, and 2 Peter 1:16-21. The Gospel reference is Matthew 5:38-48.