7 Narrow is the way of life, and broad the way of torment; prayer is able to bring a man to the house of the kingdom. This is the perfect work; prayer that is pure from iniquity. The righteousness of man is as nothing accounted. The work of men, what is it? His labour is altogether vanity. Of You, O Lord, of Your grace it is that in our nature we should become good. Of You is righteousness, that we from men should become righteous. Of You is the mercy and favour, that we from the dust should become Your image.
Give power to our will, that we be not sunk in sin! Pour into our heart memory, that at every hour we may know Your honour! Plant truth in our minds, that we perish not among doubts! Occupy our understanding with Your law, that it wander not in vain thoughts! Order the motions of our members, that they bring no hurt upon us! Draw near to God, that Satan may flee from you. Cast out passions from your heart, and lo! You have put to flight the enemy. Hate sins and wickedness, and Satan at once will have fled.
Whatsoever sins you serve, you are worshipping secret idols. Whatsoever transgressions you love, you are serving demons in your soul. Whenever you strive with your brother, Satan abides in peace. Whenever you envy your fellow, you give rest to Devils. Whenever you tell the shortcoming of others who are not present, your tongue has made a harp for the music of the devil. Whenever hatred is in your soul, great is the peace of the Deceiver. Whenever you love incantations, your labour is altogether of the left hand. If you love unseemly discourse, you prepare a feast for demons. For this is the worship of idols, the working of the lusts (of the flesh).
Source: On Admonition and Repentance (New Advent)