On Self-Will :

When a man gives up his own will he sees at once that the way of the Lord has no blemish or obstruction; when a man has a fondness for his own will, he does not see that the way of God is without blemish or obstruction. And if he happens to be cautioned about his condition, he is angry and contemptuous, and he turns away and rejects it. For how can a man have experience of this or be persuaded by the counsel of anyone, if he is mastered by self-will.

St. Dorotheos of Gaza