"How can we overcome the sinfulness that is already firmly established

"How can we overcome the sinfulness that is already firmly established 
within us? We must use force. A man labors and struggles, and so by the use 
of force he escapes from destruction, always striving to raise his thoughts 
to holiness. We are not forbidden to resist force with force. If in any 
ascetic task we exert force, however slight, then, 'remaining in 
Jerusalem', we can wait for the 'power from on high' which will come down 
upon us (cf. Luke 24:49). In other words, if we persevere in unceasing 
prayer and the other virtues, there will come upon us a mighty force, 
infinitely stronger than any we can exert. This force cannot be described 
in human language; in its great strength it overcomes our worst faults of 
character and the malice of the demons, conquering both the sinful 
inclinations of our soul and the disordered impulses of our body. 'There 
came a sound from heaven as of a rushing violent wind' (Acts 2:2); and this 
force from heaven drives out the evil that is always forcing us into sin."

St. John of Karpathos. 

"A perverse man sows strife, And a whisperer separates the best of 
friends."  Proverbs 16:28

Draw nigh unto God and He will draw nigh unto you.