1 Samuel 14:46

And Saul withdrew, not pursuing the Philistines, etc. Indeed, teachers, conscious of their own frailty, realize they are not able to track or expel all the wiles of demons; but woe to those hearts to which the repelled and cast out unclean spirits return as if to their own places.

When Jonathan's fault is discovered, when the king is found not to have fulfilled his oath, he is said to cease pursuing the Philistines, because when pastors are weighed down by their own weakness, they cannot vigorously seek the gains of others. For to cease pursuing the Philistines is to stop for a time pursuing the vices of others by preaching. For they judge that they must first attend to their own purification, and then, once purified, be watchful for the salvation of others, because while they are silent they prepare themselves, so that through their own penance, as it were, they may rise up vigorously to gain others. And because often, while the teacher, conscious of his own guilt, is silent, evil spirits are not silent toward some of his subjects, suggesting impious things to them. When the teachers are silent, the demons depart to their own places; because through the silence of the pastors, none perish except those who are not predestined to eternal life. For the places of demons are those who are not foreordained by divine foreknowledge as a dwelling of God. Hence it is said, when the first teachers were preaching: "As many as were predestined to eternal life believed" (Acts 13:48). Hence Paul says: "Whom He foreknew, He also predestined, and whom He predestined, He also called" (Rom. 8:30). Hence it is that when the apostles wished to cross into Asia, they were forbidden by the Holy Spirit (Acts 16). Therefore those who are not predestined, whether they hear the words of the teachers or do not hear them, cannot be called into the dwelling of God, because through the wickedness in which they were foreknown before the foundation of the world, they have prepared a place within themselves for malign spirits. Rightly therefore, when the pursuit of the Philistines is said to have ceased, the demons are reported to have gone away to their own places, because sometimes by God's dispensation the teachers are silent, so that while they are silent, those who are not the Lord's may be reclaimed by evil spirits. But, as I said, when after their fault the pastors are silent, they humble themselves, so that, purified, they may rise powerfully to the ministry of preaching. While they are silent, they weigh their own weakness, but by examining themselves, they strengthen themselves more vigorously against hidden enemies.