Vigilance is the virtue that makes us diligent and painstaking in fulfilling all our duties.

A teacher needs this virtue both for himself and for his students. He must watch over himself, that is, over the thoughts of his mind, over the movements of his heart, over the use he makes of his senses, and over his entire person so as not to do anything except what is good and to fulfill his obligations worthily. The faults he might commit through lack of Vigilance in any one of all these different ways would obviously jeopardize the education of the children and might even inspire them with lack of esteem and dislike of him.

A teacher should be vigilant over his students: he is their guardian angel. If his absence or his inattention (they amount to the same thing) gave the devil, who constantly goes about, an opportunity to rob them of the precious treasure of their innocence, what would he be able to reply to Jesus Christ, who will ask him for an account of their souls and reproach him with having been less vigilant to protect them than Satan was to ruin them?

From all this it follows:
1) A good teacher will not leave his class under the pretext that his colleague in the next room will maintain good order in both classes. If he is obliged to absent himself, it should be only for a very serious necessity and always for as short a time as possible. In fact, his presence contributes much to making the students more attentive by fixing and arresting their imagination; it also spares them many distractions and negligences that give rise to many faults; these lead to reprimands and punishments that the teacher might have prevented if he had not been absent.
2) When he is in class, the teacher observes everything; he misses nothing; he sees all that goes on. In this way he maintains the students in order and application. Vigilance makes them come to school on time and do all the work given them; it ensures that they keep everything they use—their books, copybooks, and papers—in good order. It can be said, in short, that the teacher’s Vigilance should extend to everything; it directs, maintains, and inspires everything: prayer, reading, recitations, catechism, the manner of following Mass, writing, arithmetic, spelling—in short, there is nothing it does not affect.
3) A good teacher watches over the general behavior of the students everywhere that he finds himself among them; acting with prudence, however, in order to prevent their noticing that they are being studied. Besides, he must continually apply himself in order to discover and to know everything that goes on, not only in the class but also in the streets, whether before or after school; and if he cannot himself see everywhere, he makes skillful use of inspectors, whom he chooses from among them; he even makes still better use of his companions, with whom he maintains a praiseworthy agreement, inspired by charity, for the good administration of the school, following in this the advice that the Apostle gave to the Romans: "Welcome one another, therefore, just as Christ has welcomed you, for the glory of God" (15:7).
4) It is especially in church that the teacher’s application, care, and attention should be concentrated on the students to maintain them in order, modesty, and the respect due to the sanctity of the place. For this purpose, he carefully avoids looking around or fixing his gaze on other objects; he restrains his curiosity and absolutely forbids himself whatever might distract him from watching over the children; he should not even stop to pay attention to the progress of the ceremonies of divine worship, if this would weaken the attention he should pay to his students; for he should be convinced that if he happened to forget himself on these points, the boys would quickly notice it and would not fail to misbehave (not being seen by him), to be scandalized, to imitate the bad example of others, and to hope to escape with impunity.
5) Finally, the Vigilance of a teacher extends even to the future. Past experience suggests to him the precautions that can be taken against what may happen and that reason may foresee. His attention, then, will lead him both to get rid of whatever might harm his students and to prevent their faults as well as the sanctions that would follow from them; he should not allow them to have, if possible, either the means or the occasions for committing sin. It is much better, in fact, to prevent evil than to punish it once committed. This is what the constant presence and the attentive eye of the teacher bring about; for as a rule the students, before doing something wrong, begin by looking around to see whether they may not be surprised and noticed by the teacher. They often fear his looks more than his corrections.

Nevertheless, the teacher’s Vigilance should not be restless, suspicious, worried, accompanied by ill-founded conjectures. Such action would be against charity and justice. It would also be mortifying for the students who might notice it as well as uncomfortable and bothersome for the teacher himself. His application should be peaceable, without agitation, trouble, constraint, or affectation; it will then be all the more effective. Just as nothing should be omitted that is required by careful supervision, so, too, we should not go to extreme lengths in our precautions. For while striving to protect the children’s morals, we should act in such a way that they do not develop into hypocrites.

The teacher should avoid the following defects as being contrary to Vigilance. He should not occupy himself with something other than his duty at any given moment; he should avoid laziness, torpor, useless conversations with the students, with outsiders, even with the other Brothers in school. He should avoid distraction of mind, distaste for school work, inattention, indolence, any kind of paralysis that robs him of the capacity for action, presumption, temerity, laziness, and sluggishness.

Besides these defects, a teacher should also avoid too much anxiety; jerky and agitated motions of the body, the head, the eyes, or the arms; negligence in observing everything the students are doing and whether they carry on their class work with due diligence; failure to apply himself carefully and constantly to whatever can establish order and diligence.

Keep watch over yourselves and over all the flock (Acts 20:28).
As for you, always be sober, endure suffering, do the work of an evangelist, carry out your ministry fully (2 Timothy 4:5).
A great treasure has been entrusted to our care and vigilance; I mean the children. Let us take all possible care of them and be on guard lest the shrewd enemy, who seeks nothing but souls, should rob us of them to make them his prey. (Saint John Chrysostom, Commentary on the First Letter to Timothy)