By His loving foresight, Jesus allowed Peter, James and John to taste for a short time the contemplation of eternal joy, so that they might bear persecution bravely.
(St Bede quoted by St. Thomas Aquinas; Summa Theologiae, III.45.1)

The mountaintop [of the transfiguration] is comfortable and the pull to stay there is incredible.
But the desert is where Christ leads us.
Christ leads us there because that’s where so many of our sisters and brothers whom he loves live.
Christ leads us there because our common destiny is as partners in this mission of God.
Christ leads us down the mountain and into the desert, because the true transfiguration, the true shining forth of God in all God’s glory, happens when we follow him there together.
Michael D Kinman