When Christ goes up the holy mountain with Peter, James and John he goes to pray and this, prayer, is quite literally a matter of life and death, of union with God or not. Here's Benedict XVI via Catholic Exchange:
Thus, for the three apostles, going up the mountain meant being involved in the prayer of Jesus, who frequently withdrew in prayer, especially at dawn and after sunset, and sometimes all night. However, this was the only time, on the mountain, that he chose to reveal to his friends the inner light that filled him when he prayed: his face, we read in the gospel, shone and his clothes were radiant with the splendor of the divine Person of the incarnate Word (see Luke 9:29).
Radiant with the splendor of the incarnate Word. Beautiful, and this:
Dear brothers and sisters, prayer is not an accessory or “optional,” but a question of life or death. In fact, only those who pray—in other words, who entrust themselves to God with filial love—can enter eternal life, which is God himself.
A terrifying warning but also a remarkable, unfathomable promise of transfiguring glory. So listen up, you heathen, and get in the business of climbing that mountain.
Oremus,
LSP
