Directions On Spiritual Training:

Life in this world is like writing on tablets: whenever a man wishes to do so, he can add to them or subtract from them, or make changes in the letters. But the future life is like writing on clean rolls sealed by the royal seal, where no adding or subtracting is allowed. Therefore, while we are still in the midst of change, let us pay attention to ourselves; and while we have power over the record of our life, which we write with our own hands, let us strive to add to it with right living and erase from it the defects of a former life. For while we are in this world, God does not affix His seal either to what is good or what is evil, up to the very moment of our exit from this life.

St. Issac the Syrian, Text #80, Philokalia