I recalled this applicable portion of
Becoming Enlightened as I read Donna Lee Wray's words.
In general a teacher is useful for gaining knowledge, and it is particularly important for a teacher of spiritual topics to be properly qualified. Chief among these qualifications are expertise in the spiritual texts and direct experience of what is being taught. Since the very purpose of Buddhist learning is to discipline the mind, a teacher of such knowledge could not help tame anyone else's mind without first having tamed her own. Therefore, a teacher must herself possess inner qualities of experiential realization and scriptural understanding surpassing those of her students.
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To teach trainees it is necessary to have a wealth of scriptural knowledge as well as acquaintance with and understanding of a range of teachings, so that when teamed with skill in techniques of instruction you can stimulate understanding in students. To accomplish this, you need to be energetically enthusiastic about improving the welfare of your students, to have only loving sympathy for them, and to forgo any personal concern about the hardships involved in explaining doctrines over and over again until they can sink in.
Just as it is important for those who want to be teachers to work at gaining these qualities, so it is important for students to understand the attributes of a good spiritual teacher and to try to find someone endowed with them. If you cannot find anyone who has all of these attributes, at least find someone who has more good qualities than defects; avoid those who defects predominate or who are in the same situation as you.
There are Tibetans in various parts of the world who are attempting to teach but are not qualified to do so. Students need to take care in order to avoid such teachers. Rushing headlong into this venture is inappropriate. Analyze first. Just as a teacher needs the power of analysis to become learned, so does a student need analysis from the very start. Buddhist doctrines aim at providing antidotes to the three poisons of lust, hatred, and ignorance, for this, discriminating wisdom is needed.
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Real lamas like Paltrul Rinpoche assume a humble posture, even though they are endowed with tremendous qualities of character. In Sanskrit the word for lama is guru, which literally means "heavy" in the sense of being possessed of many great qualities leading to altruistic activities. Nowadays, many so-called lamas have lost sight of this; the height of their teaching thrones and the elegance of their special hats do not reflect their inner state.
If you find a qualified teacher, you will value her; the best way to do this is to achieve what she teaches.
By His Holiness the Dalai Lama. Translated and edited by Jeffrey Hopkins, PH.D. pages 31-33.