Likewise, Rabbi Yaakov Neiman זצ"ל in his דרכי מוסר also explains how important it is for a teacher to be a ירא שמים. When an educator has this מדה his influence is all the more impacting on his תלמידים. For example, when a teacher relates the miraculous experiences of יציאת מצרים, and his absolute 'אמונת ה is evident, it enters into the heart of his students and leaves a lasting impression.3 This is the whole understanding behind a Rebbi resembling a malach as he notes:
לכן אמרו חז"ל אם הרב דומה למלאך ד' תורה בקשו מפיו ואם לא אל יבקשו תורה מפיו כי הכל תלוי ברב שמלמד תורה לכן מצאנו בחז"ל שאמר רב לברי' כשתשב ללמוד תורה מרבך ראה בפניו שנאמר והי' עיניך רואות את מוריך כי ראיית פני הרב מביאה יראת שמים
Therefore Chazal says if a Rav resembles an angel of Hashem, seek Torah from his mouth and if not do not seek Torah from his mouth because it all depends on the Rav who teaches Torah. Therefore we find in Chazal that Rav said to his son when you sit to learn Torah from your Rebbi make sure to see his face. As it says "And your eyes shall see your teacher" because seeing the face of one's Rav leads one to become fearful of heaven.3
Conversely, when a teacher says something that lacks conviction, his students will see this lackadaisical approach and will not absorb the message. For this reason, R’ Neiman writes elsewhere that it is crucial that a Rebbi teaches with a mindset that is completely לשמה.4
3 'דרכי מוסר, פרשת יתרו, 'והגדת לבנך 'דרכי מוסר, פרשת יתרו, 'והגדת לבנך(p.121). He begins by asking why it was that יתרו was so excited by משה’s report of the miracles that had occurred in the build up to and during יציאת מצרים, when he had already heard the same account prior? R’ Neiman answers,"אינו דומה שומע מפי הרב לשומע מפי התלמיד תלוי מי "המשמיע – “One cannot compare hearing something from the mouth of a Rov to hearing it from the mouth of the student, as it is dependent on the speaker.” This means that it was only when יתרו heard the miraculous happenings of מצרים from משה that it left a lasting impression.