Do not imagine that you will overwhelm the demon of fornication by entering into an argument with him. Nature is on his side and he has the best of the argument. So the man who decides to struggle against his flesh and to overcome it by his own efforts is fighting in vain. The truth is that unless the Lord overturns the house of the flesh and builds the house of the soul, the man wishing to overcome it has watched and fasted for nothing. Offer up to the Lord the weakness of your nature. Admit your incapacity and, without your knowing it, you will win for yourself the gift of chastity.
--St. John Climacus