We must die.

The fifth weapon is to remind oneself that we must die. This time is called the time of mercy in which God looks down day after day so that we can amend our lives from good to better. If we do not do this, we will have to render account, not only of the evils we have done, but also of the goods left undone by our negligence.
–Saint Catharine of Bologna (1413-1463)

Take up the proper weapons…

Jesus Christ gave up his life that we might live, therefore, whoever wishes to carry the cross for his sake must take up the proper weapons for the contest, especially those mentioned here. First, diligence; second, distrust of self; third, confidence in God; fourth, remembrance of the Passion; fifth, mindfulness of one’s own death; sixth, remembrance of God’s glory; seventh, the injunctions of Sacred Scripture following the example of Jesus Christ in the desert.
–Saint Catharine of Bologna (1413-1463)

In the fight against evil..

There are two things to be aware of if the fight against evil inclinations is to have any chance of success. First, our efforts will never be sufficient on their own. Only the grace of Christ can win us the victory. Therefore our chief weapons are prayer, patience, and hope. Second, one passion can only be cured by another — a misplaced love by a greater love, wrong behavior by right behavior that makes provisions for the desire underlying the wrongdoing, recognizes the conscious or unconscious needs that seek fulfillment and either offers them legitimate satisfaction or transfers them to something compatible with the person’s calling.
–Jacques Philippe (1947-

Do not let the devil…

It often happens that Satan will insidiously commune with you in your heart and say: “Think of the evil you have done; your soul is full of lawlessness, you are weighed down by many grievous sins.” Do not let him deceive you when he does this and do not be led to despair on the pretext that you are being humble. After gaining admission through the fall evil has the power to commune at all times with the soul, as man to man, and so to suggest sinful actions to it. You should answer it: “I have God’s written assurance, for He says: ‘I desire, not the sinner’s death, but that he should return through repentance and live.’ (cf. Ezek. 33:11) What was the purpose of His descent to earth except to save sinners, to bring light to those in darkness and life to the dead?
–Saint Symeon Metaphrastis (Tenth Century)

Attacks of the devil…

The crown of every good endeavor and the highest of achievements is diligence in prayer. Through it God guiding us and lending a helping hand, we come to acquire the other virtues . . . as the work of prayer is greater than other work, so it demands greater effort and attention from the person ardently devoted to it, lest without him being aware the devil deprives him of it. The greater the good a person has in his care, the greater the attacks the devil launches on him; hence he must keep strict watch, so that fruits of love and humility, simplicity and goodness – and, along with them, fruits of discrimination – may grow daily from the constancy of his prayer. These will make evident his progress and increase in holiness, thus encouraging others to make similar efforts.
–Saint Symeon Metaphrastis (Tenth Century)