The devil is both God’s enemy and His avenger (Psalm 8:2). He is God’s enemy when he seems in his hatred for God somehow to have acquired a destructive love for us men, persuading us by means of sensual pleasure to assent to the passions within our control, and to value what is transitory more than what is eternal….He is God’s avenger when–now that we have become subject to him through sin–he lays bare his hatred for us and demands our punishment.
For nothing pleases the devil more than punishing us….he does this not with the intention of fulfilling God’s command, but out of the desire to feed his own passion of hatred towards us, so that the soul, sinking down enervated by the weight of such painful calamities, may cut itself off from the power of divine hope, regarding the onslaught of these calamities not as a divine admonition but as a cause for disbelief in God.
~St Maximos the Confessor
Prayerful Life 