Just as a person is commanded to honor his father and hold him in awe, so, too, is he obligated to honor his teacher and hold him in awe.
[Indeed, the measure of honor and awe] due one's teacher exceeds that due one's father. His father brings him into the life of this world, while his teacher, who teaches him wisdom, brings him into the life of the world to come.
[Accordingly,] if he saw a lost object belonging to his father and one belonging to his teacher, the lost object belonging to his teacher takes precedence. If his father and his teacher are both carrying loads, he should relieve his teacher's load, and then his father's. If his father and his teacher are held as captives, he should redeem his teacher, and afterwards, redeem his father. However, if his father is [also] a Torah sage, he should redeem his father first.
[Similarly,] if his father is a Torah sage - even if he is not equivalent to his teacher - he should return his lost article, and then that belonging to his teacher.
There is no greater honor than that due a teacher, and no greater awe than that due a teacher. Our Sages declared: "Your fear of your teacher should be equivalent to your fear of Heaven."
Therefore, they said: Whoever disputes the authority of his teacher is considered as if he revolts against the Divine Presence, as implied [by Numbers 26:9]: "...who led a revolt against God."
Whoever engages in controversy with his teacher is considered as if he engaged in controversy with the Divine Presence, as implied [by Numbers 20:13]: "...where the Jews contested with God and where He was sanctified."
Whoever complains against his teacher is considered as if he complains against the Divine Presence, as implied [by Exodus 16:8]: "Your complaints are not against us, but against God."
Whoever thinks disparagingly of his teacher is considered as if he thought disparagingly of the Divine Presence, as implied [by Numbers 21:5]: "And the people spoke out against God and Moses."