1 Samuel 17:51

Seeing that their strongest man had died, etc. Seeing that the unclean spirits were defeated and prostrated by the incarnation and passion of the Lord, they fled from the hearts of the believers. And all the strong ones in the Church, gathered from both the circumcised and the uncircumcised, arose and lifted up a voice terrifying to the wicked of divine preaching and praise, and pursued them until they recognized that they were to be humbled by Christ, and as it were submerged in the valley of dejection, who had previously boasted of setting up their camp on the mountain of pride against Him; and the fugitives might withdraw to the hearts, which they had previously inhabited evilly, plundering completely every fruit of piety and faith. For the gates of Accaron, that is, of barrenness, the fleeing Philistines reached, when the malignant spirits, repelled from the minds of the faithful, once again referred to their teachers. They entered the walls of the city of vanity and falsehood itself, when they also compelled the ignorant crowd to increase their unfruitful work worthy of fire. But they also reached Geth, that is, the press, when they drew out the hearts of the deceived to torment the good ones with unjust persecution. All these can also be understood in the same order even about perverse humans.

But our armor is Christ; it is that which the apostle Paul prescribes when, writing to the Ephesians, he says, "Take unto you the whole armor of God, that you may be able to withstand in the evil day;" and again, "Stand, therefore, having your loins gird about with truth, and having on the breastplate of righteousness; and your feet shod with the preparation of the gospel of peace; above all, taking the shield of faith, wherewith you shall be able to quench all the fiery darts of the wicked: and take the helmet of salvation, and the sword of the Spirit, which is the word of God." Armed with these weapons, king David went forth in his day to battle. Taking from the torrent's bed five smooth rounded stones, he proved that, even amidst all the eddying currents of the world, his feelings were free both from roughness and from defilement. Drinking of the brook by the way, and therefore lifted up in spirit, he cut off the head of Goliath, using the proud enemy's own sword as the fittest instrument of death, smiting the profane boaster on the forehead and wounding him in the same place in which Uzziah was smitten with leprosy when he presumed to usurp the priestly office; the very place also in which shines the glory that makes the saints rejoice in the Lord, saying, "The light of your countenance is sealed upon us, O Lord." Let us therefore also say, "My heart is fixed, O God, my heart is fixed: I will sing and give praise: awake up, my glory; awake, psaltery and harp; I myself will awake early"; that in us may be fulfilled that word, "Open thy mouth wide, and I will fill it"; and, "The Lord shall give the word with great power to them that publish it." I am well assured that your prayer as well as mine is that in our contending, the victory may remain with the truth. For you seek Christ's glory, not your own: if you are victorious, I also gain a victory if I discover my error.