1 Samuel 14:20

Saul and all the people cried out, etc. Jews, Gentiles, and heretics, although they are all enemies of the Church, wound each other with the sword of the word. The Jews themselves fight among themselves through the Pharisees and Sadducees: likewise heretics and pagans, with so much dissonance of various doctrines and sacred matters, bring no less wars among themselves than with the Church. But there is one, he says, my dove, my perfect one (Canticles VI): she is the only one of her mother, the chosen one of her who bore her, from whom Jonathan, that most valiant leader, received the name of virtue, that he might be called the gift of the dove; whose perpetual peace even the discord of the wicked serves. Hence it follows:

What is this sword, if not the sword of the spirit, which is the word of God? For those who in innumerable places have been converted to the service of almighty God, because they cling inseparably to the word of God, each one holds a sword, as it were, close at hand. Therefore the sword of each one is turned against his neighbor, when those who have been converted in monasteries pierce one another in turn with the word of God and utterly slay the carnality within themselves. For they are killed, as it were, by mutual wounds, when one strikes another with the word of God and extinguishes whatever lives carnally within him. Because they had recently been converted and had fallen away from secular life, they were signified by the type of the Philistines. Or the sword of one is turned against his neighbor when, through the exhortation of the converted, sinners not yet converted are turned to the Lord; when not only those who are in authority profit others by the word of preaching, but the multitude of subjects strive to instruct as many as they can by words and examples, and endeavor to draw them away from the desires of the present life as though slain, and to present them alive to eternal life. Indeed, we see these gains from the slain now spread throughout the whole Church across the entire world, because whoever now lives to God through divine grace appears dead to this world by the blade of mutual charity. For the sword of each one is turned against his neighbor, because all the elect strengthen one another in turn within the holy Church and inflame one another toward the heavenly homeland by the zeal of mutual preaching. And because an innumerable people is daily won for God, it is rightly added there: 'And the slaughter was exceedingly great.' What is exceedingly great is that which can somehow be recognized in its magnitude, but whose excellence cannot be comprehended. He had raised his eyes to this exceedingly great slaughter who said: 'But to me your friends are exceedingly honored, O God; their rule is exceedingly strengthened; I shall count them, and they shall be multiplied beyond the sand' (Ps. 138:17). The exceedingly great slaughter can also be understood to mean not only that many were slain, but that they were slain well. This is indeed seen to happen in the conversion of sinners, when they so abandon their past that they never come back to…