Thus, the inner ascent from zeal to zealous dedication to God is nothing other than the revelation and appearance to our consciousness of God’s work in us, or the working of our salvation and purification. The zealot becomes enlightened about this reality through frequent failures met in spite of all his efforts, and unexpected and great successes met without particularly trying. Mistakes and falls are especially enlightening as they bereave us of grace. All of these bring a man to the thought and belief that he is nothing, while God and His all-mighty grace are everything.

St. Theophan the Recluse, The Path to Salvation: A Manual of Spiritual Transformation