1 Samuel 14:15

And the earth was troubled, etc. So that those who are wise in earthly things may be troubled by the deeds of heavenly men; so that demons, terrified and groaning, may recoil from attacking men, their malice broken and their strength shattered; this is not a work of human virtue, but a miracle of divine mercy. Hence Paul, when he said he had labored more than all of them, immediately added: "Yet not I, but the grace of God which was with me" (1 Corinthians 15).

And a miracle happened in the camps through the fields, etc. By the miracle, strength and virtue are given to the just among those who are reprobates camping through the fields, having hearts astray, weakened by both malice and an abundance of pleasures. Hence the blessed apostle Peter, when he described the excess of those who, as if residing in the field of free pleasure, live in desires, drunkenness, revelries, drinking bouts, and illicit idolatries, added, saying: "In which they are surprised that you do not run with them into the same flood of debauchery" (1 Peter 4). But also the spiritual adversaries, although fierce plunderers of human salvation, are accustomed to be astonished at the deeds of perfect men, and to yield to the devotion of perfect prayers and other virtues.

All who are perfect do not cease to marvel at the power and wisdom of almighty God in all things that have been made or are being made. Hence the Psalmist too, pressing on with divine praises, says: "God is wonderful in His saints; the God of Israel Himself will give power and strength to His people; blessed be God" (Ps. 67:36). Hence Moses confesses to the same Lord, saying: "Who is like You among the gods, O Lord? Who is like You, glorious among the saints, wonderful in majesty, working wonders?" (Exod. 15:11). He is indeed called wonderful in His saints because the more loftily they behold divine things, the more wondrously they are struck with amazement, for assuredly in the highest contemplation they see things at which they marvel, not things they can comprehend by reason. Therefore, whenever certain new things occur beyond ordinary experience that carnal and simple people wonder at, a miracle is said to happen among the fields. For in comparison with the saints, they are like rustic people who do not know how to marvel at so many ancient works of the Creator, so many arrangements of times, and so many orders of creatures. Rightly, then, all are generally included under that same dullness of rusticity, when it is added: (Verse 15.) "But also all the people of their garrison who had gone out to plunder were struck with astonishment." What garrison do they call, if not that of the Philistines? What is it then that the Philistines marvel at, except that sometimes other sinners, astonished, behold the conversion of sinners, and while they recognize the goodness of God in their visitation, they are kindled to a similar resolve of conversion? For the people of the garrison go out to plunder when they do not fear to act perversely. For what anyone dares to do while God forbids it, while the Scriptures threaten, while teachers oppose it, he strives as if by violence to seize for his own uses. If anyone wishes to understand demons by this people, he may, because they go out to plunder when they bring violent temptations and lead captive the souls of sinners. This people is certainly said to be astonished, because they do not understand by what grace converted sinners receive a penitent heart, which demons cannot possess. But while sinners come to their senses, they benefit both themselves and others, because many are corrected by their example. Whence it is…