1 Samuel 17:3

Yet there stands Goliath, monstrous in his pride, swollen with his earthly power, confident that he can do everything by himself, with his head, hands and entire body clad in much bronze, having his own armor bearer behind him who, though he does not himself fight, nevertheless furnishes this Goliath with all kinds of aid in bronze and iron. And it is not surprising if Scripture, foreseeing our present situation, comments appropriately when it says, "The Philistines were standing on top of the mountain on this side," since the individual who is attacking the [Pelagian] heresy is now being banished from the church, while the heretic is found to be nourished at its very breast! Because of this, it is so stated by the Holy Spirit that on the other side Israel was standing, while on this side, the enemy. And such is often the way. For even King David, who was always the righteous father toward his unrighteous son, having laid aside his royal robes, was forced to flee from Jerusalem, whereupon the tyrant Absalom immediately entered. There now stands Goliath—oh, what sorrow!—on this side, that is, within the church; and he not only stands but even offers challenges. And at the same time, over the course of many days, he reproaches holy Israel for its well-known fear of God.

And the Philistines stood on the mountain on this side, etc. And even to this day, unclean spirits contending against the Church stand lifted up with proud boasting, after the example of that first proud one, of whom it is written in the Revelation of John: And as a great mountain burning with fire, it was cast into the sea (Rev. VIII). And the soldier of righteousness stands, not relying on his own arms, but exalted by His help, who says: A city set on a mountain cannot be hidden (Matt. III). And there was a valley between them; the place of their conflict is the temporal life itself, in which the good and the wicked fight among themselves, and the tree of life in the middle helps and refreshes the worthy, condemns and casts out the wicked; and that same life of the world is common, and the just pass through it, hoping in Christ as the highest mountain, with diligent mind, saying: But our conversation is in heaven (Phil. III). And the reprobates through the devil, by swelling up, despise the society of their neighbors and transcend. Against this the Apostle admonishes the faithful, saying: Be not wise in your own conceits, but condescend to men of low estate (Rom. XII). For the Philistines represent no less the perverse men than the angels, serving in the one and the same kingdom of the devil.