Remember thy last, and thou shalt never sin unto eternity

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 6 ~ On Remembrance of Death

¶24. It is impossible, someone says, impossible to spend the present day devoutly unless we regard it as the last of our whole life. And it is truly astonishing how even the Greeks have said something of the sort, since they define philosophy as meditation on death.
This is the sixth step. He who has mounted it will never sin again. Remember thy last, and thou shalt never sin unto eternity.