1 Samuel 31:3

"I will inebriate my arrows with blood, and my sword will devour flesh." These are the spiritual arrows of the Lord with which he strikes the heart of the human race and drains our spiritual blood. For just as Christ himself is called an arrow, chosen by the hand of the Father, so also his apostles are named arrows metaphorically, whom his powerful bow dispersed throughout the entire breadth of the world. Perhaps Jonathan shot the same arrows as a sign that David should flee from the hand of his cruel king. And Saul was struck by these very arrows, that such an obviously worthless king would be deprived of the Israelite kingdom. These are the arrows that drink the blood of our infidelity and carnal sins, for which reason it is said concerning them: "They will eat the sins of my people."

The entire weight of the battle turned upon Saul, etc. The gentiles were exerting all their strength to destroy the kingdom of Judea. And men most adept in the arts of deception drew near to him, and the leaders of that kingdom were severely seduced and corrupted by them, who, by seizing the simplicity of the truth from their hearts, inflicted a multi-faceted wound of fraud and cunning. For just as an enemy's sword signifies an open enticement to idolatry and graver sins, so the subtler arguments of deception are represented by an arrow. Saul did not perish by the sword of the Philistines, but by arrows; because the leaders of the Jewish kingdom did not perish, with the kingdom, by open crimes, which no one would doubt to be deadly, but rather by those acts which, under the guise of piety, bore the most impious poison of death. For example, when God says: "Honor your father and mother," they, on the contrary, taught their listeners to say to their parents: "Whatever gift is from me, will benefit you," and thus completely cease to honor them. Similarly, they said: "Whoever swears by the temple, it is nothing; whoever swears by the gold of the temple, is obligated," and other such things, which the Lord sternly reprimands them for in the Gospel, especially that they killed the very Lord of the Law and the Gospel as if He were a transgressor of the Law. All of these arguments of sins are imitated by the gentiles for cunning, when they turn a mind trained in philosophical studies to nefarious arts, undoubtedly falling by the arrows of the Philistines. However, nothing prevents the archers from being understood as unclean spirits, whose deceptions caused their ruin.