Metropolitan Anthony Bloom elaborates on what the Orthodox exhortation to “remember your death” really means.
St. Paul in one of his epistles says that we must make haste to live because time is deceptive. We live all the days of our life as though we were writing hastily, carelessly, a draft of life that one day we will copy in fair hand. It is as though we are just preparing to build, collecting all that will later be organized into beauty, harmony, and meaning…. But years pass and we never do it.
This is not only because death comes, but because at every period of life we become unable to do what the previous period would have allowed us to do. It is not in our mature years that we can achieve a beautiful and meaningful youth, as it is not in old age that we can reveal to God and to the world what we might have been in our years of maturity. There is a time for all things, but once the time has gone, these things can no longer be done.
Victor Hugo said that there is fire in the eyes of the young, but there should be light in the eyes of the old. The time of the glowing fire passes, the time of light reaches us, but when the time of being a light has come, we can no longer do those things that can be done only in the days of our flaming. Time is deceptive. When we are told that we must remember death, it is not in order to give us a fear of life; it is in order to make us live with all the intensity that we could possibly have if we were aware that every moment is the only moment we possess…. And so the remembrance of death seems to be the only power that makes life ultimately intense.
–Metropolitan Anthony Bloom, From Living Orthodoxy in the Modern World
(I put a photo of St. Paisios as an example of someone who shined with a bright light.)