EXOD262 A teacher should respect his students. … Rashi comments: "Choose for us," that is, for me and for you; Moshe compared Yehoshua [Joshua] to himself. From here the Sages have said, "Let the honor of your student be held In esteem by you as your own honor." Cited in Yorah Daiah 242:33 ... If his students do not understand what they have been taught, a teacher should not be angry with them. rather, he should repeat the lesson until they do understand (Rambam, Hilchos Talmud Torah 4:4; Yorah Daiah 246: 10,11). A student should not say, "I understand" when he really does not understand. He should ask for the lesson to be repeated until he comprehends, even if it entails several repetitions. If his teacher grows impatient with him, he should say ,"Teacher, what you are teaching is Torah and I must learn it; for my mental capacity is limited. (ibid.). ... A teacher should not grow angry at his students for failing to understand what he taught only if their lack of comprehension stems from the difficulty of the subject matter or the students lack of ability. If, however, if they do not understand because they are too lazy to study properly, a teacher should act angrily towards them and may even embarrass them. In reference to this the sages (Ksubos 103b) have said that a teacher should instill fear into his students. (Rambam, ibid 4:5, Yorah Daiah 246:11). Besides possessing a thorough grasp of the subject matter that is to be taught, a teacher must be sincerely interested in the welfare of his students. He should try to help them with their personal needs and problems, (Shivti B'bais Hashem, pp. 16, 30) and should show them understanding and sympathy. A teacher should be impartial with his students (see Shabbos 10b; Shivti B'bais Hashem, p.33). He should admit his own mistakes (Zevachim 101a; ibid. p.22). He should not make promises or threats that he does not intend to keep (see Sukah 56b; ibid. p.35). A teacher should not use sarcastic remarks or ridicule, rather he should discipline in a quiet, dignified, and positive manner (see Bava Metzia 58b; ibid, p.32).