In the Letter to the Ephesians, the apostle Paul tells us about the armor of the christian:
Put on the full armor of God, so that you can take your stand against the devil's schemes. For our struggle is not against flesh and blood, but agains the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms. Therefore put on the full armor of God, so that when the day of evil comes, you may be able to stand your ground, and after you have done everything, stand. Stand firm then, with the belt of truth buckled around your waist, with the breastplate of righteousness in place, and with your feet fitted with the readiness that comes from the gospel of peace. In addition to all this, take up the shield of faith, with which you can stinguish all the flaming arrows of the evil one. Take the helmet of salvation and the sword of the spirit, which is the word of God. Ephesians 6:11-17
The apostle Paul makes us an exortation to spiritual warfare, the reference in the gospels to this concept is frequent, the idea behind this, it is how to confront the suffering that generates the evil. The world is a certain sense belongs to those who are oppose to the beatitudes and for this we need more than the instruction given by wisdom.
Aristoteles makes an interesting analysis in his book about Metaphysics: the nature of evil is hate. A nature is towards what the being tends in its development. The evil in its development tends towards the hate and the fury. Fighting and confronting hate, seeking the truth through perseverance is the essence of spiritual warfare.
For Paul, justice is not enough. The truth, that is to say the precise and the exact, is the belt, the righteousness is the breastplate, the peace the footwear to walk, the faith (to accept the creed) the shield, the salvation the helmet, and the sword the word of God (inspired wisdom).
Examples of the spiritual warfare and its armor are the passion of Christ where Jesus suffers the betrayal of Judas and he is crucified; St. Augustine in his book Confessions where the author narrates his resistance to sin to achieve the truth and the salvation; and the personage of Job in his Book where he resists the stalks and misfortunes of evil.