4 Then said Saul unto his armourbearer, Draw thy sword, and thrust me through therewith; lest these uncircumcised come and thrust me through, and abuse me. But his armourbearer would not; for he was sore afraid. Therefore Saul took a sword, and fell upon it.
[AD 735] Bede on 1 Samuel 31:4
And Saul said to his armor-bearer: Draw your sword, etc. The armor-bearer of Saul signifies the doctors of the law; for just as the arms and arrows of the Philistines are the deceits of the wicked, so on the contrary, the arms of the Israelites ought to be mystically understood as the words of spiritual doctrine, by which the people of God had to fortify themselves against all dangers. But Saul, wounded unto desperation by the archers, preferred to die by the sword of his armor-bearer rather than by that of the uncircumcised, because the rulers of the kingdom of the Jews, once having set the purpose of dying in their sins, preferred to be destroyed by their doctors who were dissolving the commandments of the law and thus teaching them, rather than to be polluted by the company of the gentiles, whom they called common and unclean. Moreover, they feared to enter the praetorium of a gentile, so that they would not be contaminated, but could eat the Passover (John XVIII). Nevertheless, they did not fear to contaminate that same Passover, turned for their ruin by the law, which they had received, with the blood of the innocent.

[AD 735] Bede on 1 Samuel 31:4
And his armor-bearer did not want, etc. There is no doubt that among the reprobate teachers of the law there have been some who, through a sinister interpretation, did not want the sharpness of the word to kill their own listeners, and yet those listeners turned to their own ruin either by despising or, what is worse, by blaspheming the things rightly said by their teachers. Upon seeing their spiritual death, that is, their obstinacy in sinning, those ministers of the word, deteriorated over time, saw that the testimonies of the law, which they had feared to interpret wrongly, when contemptuously disregarded, became an occasion of downfall for them. We regret to acknowledge that the same things happen often today. But even heretics, wounded by their own sins, when they twist the words of divine scriptures into arguments for their error, surely turn their own weapons upon their own chests as they are about to die; and any brother, even remaining in the unity of the catholic Church, when he defiles any skill he has learned for the common good of the Church and those among whom he lives with the contagion of pride, arrogance, avarice, or any other vice, miserably pierces himself with his own sword, because that which ought to have been defended against the enemy, instead aided the enemy.