If even one passion becomes a habit with a person, it will torment him. ( Abba Dorotheus )

If even one passion becomes a habit with a person, it will torment him. Sometimes, even one evil habit can surmount many good deeds performed by a person. For example, if even only one talon of an eagle’s foot gets entangled in a net, he would be captured. Similarly, a soul can fall into the hands of the enemy because of one passion. Consequently, don’t allow even one passion to turn into a habit, but constantly pray to God so as not to succumb to temptation. If through our weakness we find ourselves conquered, let us force ourselves to arise immediately, begin to lament before God’s goodness and begin again to be vigilant and dutiful. And God seeing our good intentions, humility and penitent heart, will offer His helping hand and will deal with us according to His mercy.

Abba Dorotheus

Struggle against lust

A certain monk had a struggle against defiled lusts. He got up and night and went to the elder and confessed to him the thoughts that were drawing him to defilement. The elder calmed him and the brother, have benefited, returned to his cell. But the struggle rose up against him again, and again he went to the elder. He did this a few times. The elder did not grieve him, but said, “Don’t give up, but it is better that you come to me whenever the demon disturbs you, and repel him by exposing your thoughts. By such a repulsion he will pass you by. For nothing so burns the demon of defilement as the revelation of his deeds [in confession before a spiritual father]. And nothing makes him so happy as the hiding of thoughts.” Thus the brother came to the elder eleven times, repelling his thoughts, and the brother’s temptation ceased.
  
Ancient Patericon

http://agapienxristou.blogspot.ca/2013/03/struggle-against-lust.html

Struggle for Christ ( Elder Joseph the Hesychast )

Without a struggle and shedding your blood, don’t expect freedom from the passions. Our earth produces thorns and thistles after the Fall. We have been ordered to clean it, but only with much pain, bloody hands, and many sighs are the thorns and thistles uprooted. So weep, shed streams of tears, and soften the earth of your heart. Once the ground is wet, you can easily uproot the thorns.

Elder Joseph the Hesychast