A monk should always act as if he was going to die tomorrow; yet he should treat his body as if it was going to live for many years. The first cuts off the inclination to listlessness, and makes the monk more diligent; the second keeps his body sound and his self control well balanced.
Now, meditating on death as a spiritual discipline is long attested in Scripture (Ecclesiastes 12:1-7) and other authors of antiquity, like Epictetus:
Day by day you must keep before your eyes death and exile and everything else that seems frightening, but most especially death; and then you’ll never harbour any mean thought, nor will you desire anything beyond due measure. (Enchiridion 21)
But what interested me in Evagrius’ little note on watchfulness was his concern that the monk care for his body. We should live each day as though eternity awaits us on the other side, but we should care for our body as though we were going to live a long time. In the current year, it is apparently verboten to pursue physical ideals or attempt to establish them at all, but the fact is that insofar as it depends on us (for some bodily care is literally out of reach due to injury or congenital difficulties), the way we care for our bodies is reflective of and contributes to our spiritual well-being. Why? Because our body is our first bit of the earth to rule (Genesis 1:26-2:7) and because the state of our body directly affects our state of mind.