Our natural state is darkness in comparison to divine grace. How much more so when the gloomy demons approach us, which are dark
by nature! So when the light of grace comes, everything evil disappears---just as when the sun rises the darkness leaves, and we can clearly see even the smallest details that escaped notice before dawn. But once the sun sets, the darkness overtakes us naturally once more, and whoever walks in the darkness suffers great damage and
Likewise, the same thing happens to us in our spiritual journey. When we have divine light, we can see everything clearly, and the demons flee far away, as they are unable to stand before divine grace. But once divine grace leaves again, the darkness remains, that is, our natural state. Then the thievish demons come and fight us.
And so, since our nature is subject to so many changes, and since in a time of darkness we, without the discernment of divine grace, work many deeds that harm us, and since many times we are mortally wounded by the enemies, because it is dark and we cannot see the enemies that are hiding.
Therefore, we should never grow bold and think that everything we do is pleasing to God, nor should we trust in our own weapons and skill. But we should call upon divine aid and trust only in it, and should say with great fear, for we do not know, "I wonder, is what I say pleasing to God, or do I perhaps sadden Him?" And in times of change, we must be patient.
"Epistle to a Hesychast Hermit"
(Chapters XI & XII & Epilogue)
From the book "Monastic Wisdom"