Okay, so there are two circumstances when a teacher should not tell the truth. First, a good teacher will not tell the truth when he is seeking to maintain confidence. In other words, a teacher can and should cultivate a relationship with the students. These relationships should be characterized by trustworthiness in secrecy. A teacher interacts with students both in the classroom and outside the classroom. Teachers should seek to remain respectful of the things that need to be kept secret from public view. In other words, if a student says something that is private or personal, then the teacher should not broadcast it. This may sound mind numbingly fundamental, but the simple fact is some teachers are prone to public broadcast. A teacher may not name names, but he may manifest an attitude in front of the students that expresses impatience or anger at his students in general. For instance, I once had a teacher that spent a good 5 to 10 min. castigating the class for their hypothetical absence. In other words, he was trying to warn us from not using out on class. This is certainly good advice. However, he proceeded to talk about how he's had students in the past continually abstain from showing up. When he said these things he said very angry. In my judgment, this is a lack of self-control. It is good to talk about the importance of class attendance, but it is unnecessary to express anger in the presence of a class that has yet to violate teachers rules. The teacher should have merely expressed the importance of attendance and lay down the consequences for lack there of. He should have kept his anger a secret. The consequence of this lack of secrecy demonstrates a lack of self-control and trustworthiness.
Second, a good teacher will not tell the truth before the student is ready. In other words, students only learn what they are ready to learn. Generally speaking, most classroom will be full of a handful of people that are ready to learn, but you must always take into account the students that are not fully ready to learn. For example, I once attended a class that concerned broadly the topic of pastoral leadership. The teacher began his lecture with a quick survey of vocational interest. He said, now raise your hand if you are going to be a pastor. Most of the class responded by raising their hand, but I was among the few that did not because do not have the vocational goal of becoming a pastor. The teacher then proceeded by saying, "good, then a great many of you need to understand the importance of pastoral leadership…" The teacher continued to only address those that were going into pastoral leadership. The mistake that he made was that he failed to make an argument for why others should also be concerned about this topic. The beginning of every lecture should be concerned with establishing the necessity and importance of the topic. But the importance of the topic should extend as far as I can go to as many people as I can go. The teacher could have strengthened the force of his topic by arguing why many more people than just pastors should be concerned about this topic. Those that are aspiring pastors have already bought in. The people that need the sold are the ones who do not believe or may not believe the subject is pertinent. If you can make an argument for your topics importance to those people, then you will certainly win over those that are readily concerned. In this case, the teacher failed to uncover a secret. He neglected to tell the truth to those who did not know how to be ready for the truth.
Learning readiness can also manifest itself in terms of antagonism. If a student is antagonistic to a topic, then quite frankly you need to disarm him before you can inform him. There's no sense in trying to get information that he strongly believes is irrelevant or perhaps untrue.
In conclusion, a teacher must not just be concerned with the art of proclaiming what is true, but he must also be concerned about discretion and reference. He must learn to discern when to tell the truth and when not to tell the truth. He must learn to demonstrate reverence for his topic and his students. Above all he must work hard at extending trust both in the classroom and outside the classroom.