When the mind begins to flourish in its love for God, the blaspheming spirit commences to tempt it, instilling such thoughts that no human being could think of but only the devil — their father. And he does this from his jealousy of the God-loving Man, who in accepting such thoughts as his own, he would become despondent and cease having the boldness to turn to God with prayer. But the cunning one obtains no gain from his wiles, because he makes us more resolute, because in warring against him, we become more experienced and more sincere in our love toward God.
Saint Maxim the Confessor
