Guru and Student

When the teacher finds from signs that knowledge has not been grasped or has been wrongly grasped by the student, he should remove the causes of non-comprehension in the student. This includes the student's past and present knowledge, want of previous knowledge of what constitutes subjects of discrimination and rules of reasoning, behavior such as unrestrained conduct and speech, courting popularity, vanity of his parentage, ethical flaws that are means contrary to those causes. The teacher must enjoin means in the student that are enjoined by the Śruti and Smrti, such as avoidance of anger, Yamas consisting of Ahimsa and others, also the rules of conduct that are not inconsistent with knowledge. He [teacher] should also thoroughly impress upon the student qualities like humility, which are the means to knowledge.
— Adi Shankara, Upadesha Sahasri 1.4-1.5[46][47]

The teacher is one who is endowed with the power of furnishing arguments pro and con, of understanding questions [of the student], and remembers them. The teacher possesses tranquility, self-control, compassion and a desire to help others, who is versed in the Śruti texts (Vedas, Upanishads), and unattached to pleasures here and hereafter, knows the subject and is established in that knowledge. He is never a transgressor of the rules of conduct, devoid of weaknesses such as ostentation, pride, deceit, cunning, jugglery, jealousy, falsehood, egotism and attachment. The teacher's sole aim is to help others and a desire to impart the knowledge.
— Adi Shankara, Upadesha Sahasri 1.6[48]

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