Lama Zopa Rinpoche:
In order to realize emptiness we need three conditions: continual practice of purification of defilements and obstacles, continual accumulation of merit and a pure devotional mind looking at our guru as buddha. If, on this basis, we meditate on the actual body of the path, because these prerequisites are there, even a little meditation on emptiness, or just hearing and concentrating on a few words, can cause experiences to come. Just reading a few pages might be enough. On the other hand, if we have no such devotion, nothing clicks. Because we have not engaged in the intensive collection of merits or purification of defilements, our mind is very dry.
Also, to meditate on emptiness effectively in our everyday life, we again need to have very strong guru devotion in our mind—devotion toward all the gurus with whom we have a Dharma connection. Even if we have received just the oral transmission of a mantra, from our side we should regard that teacher as a guru, a buddha. The explanations of the Buddha and Buddha Vajradhara can help you do this. You can also rely upon the experiential realizations of highly attained valid lamas, such as Lama Tsongkhapa, and those from other traditions, such as Milarepa.
Also, you can use your own personal and special experiences to support such quotations and reasonings. The basic point is that the thought of guru devotion should enter your mind exactly as it entered theirs. Your mind should not be dry of devotion like a hot desert, where there is no water and nothing grows. Your mind should be filled with the moisture of devotion so that everyone with whom you have made a Dharma connection appears as a buddha. It should be pure and positive toward them. Whether the topic be emptiness, compassion or impermanence, if your mind is pure and positive toward your gurus you will find it very easy to have experiences.
The stronger the feeling of guru devotion, the stronger the realization. For example, you may have been doing a prayer such as the Lama Chöpa (Guru Puja) for many years without experiencing any feeling, but when you do it with strong devotion, then suddenly every single word gives rise to a great taste, a great richness of meaning; while reciting the prayer you feel its meaning in your heart. Rather than just saying it, you are experiencing it. Then this prayer that you have been reciting for such a long time becomes very precious. When you recite the prayer with guru devotion there is no gap between the recitation and yourself. There’s no separation. You feel oneness with it, a sense of connection such that your heart is transformed into the meaning. At the same time, while you are feeling profound guru devotion, you are collecting extensive merit and engaging in very powerful purification as well.
We should think here of the ultimate, or absolute, guru. Even though appearing in different bodies, all the past, present and future gurus are one. This is the case right up until we achieve full enlightenment. As mentioned in the Lama Chöpa, the essence of the guru is the primordial savior who we meet in different forms in our different lives. We have received this precious human body only because, in the past, we met the Buddhadharma through them and received teachings on karma and morality—what is to be practiced and what must be abandoned. Through them we met the Mahāyāna Pāramitāyāna and Vajrayāna teachings and observed the vows of those vehicles. As a result, in this life, we have again met all three levels of the Buddha’s teachings. It is only due to our guru’s kindness that we have the choice of what to practice, right this second.
Because our mind is a causative phenomenon—which means it depends on causes and conditions—at the beginning we might think that it is impossible to see this person as a buddha. You just can’t figure it out. There seems to be no way that you can have that realization. However, through the conditions we have established by creating extensive merit and engaging in powerful methods of purifying the mind, just a few words from a single stanza of the Guru Puja describing the qualities of the guru as the embodiment of all the buddhas, suddenly, with just a little meditation, it just clicks. We realize, totally, that this teacher is this deity. From deep down in our heart there is neither question nor doubt.
The more our mind is cleansed, the more realizations and experiences spring up, just as a plant arises from a seed. This is because we (and all other sentient beings) have the buddha nature within our mental continuum. Realizations come from within. In the beginning, our mind is ordinary and stubborn, as hard as a rock, but when we practice correctly it can no longer stay in that disturbing way. Correctly is here a very important word. What those endowed with realizations discover is that one buddha is all the gurus and one guru is all the buddhas. We realize one hundred percent that the guru who is our virtuous friend without any mistakes at all is the deity; our gurus have only enlightened qualities. Such understanding is the quality of having realized guru devotion, the root to the path to enlightenment.
THE GURU IN ORDINARY ASPECT
We can generate faith in a buddha by understanding how his ability to benefit numberless sentient beings is much much greater than even a bodhisattva. As soon as a sentient being’s karma has ripened, without any effort, motivation or thought, the buddhas spontaneously manifest the inexpressible. Faster than a finger snap and without a second’s delay, they reveal the exact method suited to fit that particular moment of that being’s karma. In this manner they lead sentient beings from happiness to happiness all the way up to enlightenment. I am not saying that I am buddha. What I want to explain is how we are all led by all the buddhas in the various forms of the gurus.
In our own case, because we have much more merit than others, we have the opportunity to receive teachings that they don’t. However, though giving teachings is the highest way a buddha can guide, they can benefit sentient beings in other ways. But for our part, we have the karma to be able to see and communicate with their manifestations such as His Holiness the Dalai Lama, Lama Yeshe and the teachers in our Dharma centers—they appear to us according to the impure karmic vision of our impure mind. This means they also manifest with a saṃsāric body showing sicknesses and mistaken actions and appear to have delusions such as ignorance, anger, attachment, pride and jealousy.
We don’t have the karma to see a purer manifestation of the buddha, one unmarked by a single mistake or suffering. Thus a buddha aspect without a single fault is unable to guide us—if we cannot see them directly they cannot guide us. What we must understand is that there is a correlation between the manifestation of an ordinary form with suffering, mistaken actions and a deluded mind and our own obscured mind and impure karma. Similarly, animals, who are lower than us, are unable to receive teachings and guidance from even in this ordinary form suited to our impure level of mind. We should think as follows:
Through the guru appearing in ordinary aspect according to my impure mind and karmic connection, numberless buddhas guide me, as do Guru Śākyamuni Buddha, Maitreya Buddha, Tārā, Guhyasamāja, Cakrasaṃvara [Heruka] and Vajrayoginī as well.
Gyalwa Ensapa mentions how all the past buddhas and bodhisattvas will work for transmigratory beings in the present if we are able to recognize them gathered together in the form of the qualified guru who is able to guide. When we receive initiations and teachings, commentaries and lungs, we should think about and realize the guru’s role and qualities in this way. Likewise, when our guru gives us advice or does some activity we should see it as the advice or action of all the buddhas. Our guru’s advice becomes Mañjuśrī’s or Tārā’s direct advice to us.
By following the reasonings in this way we come to see why the guru is kinder than all the numberless buddhas. Those who haven’t received teachings on guru devotion will find it helpful to remember and think like this every day, for this is the heart of the guru yoga meditation.
See also post
Full publication details of cited texts are found in the bibliography
 See Zopa, Heart, 201–41, for an elaborate account of how these two lineages present this point. See also Tsongkhapa, Great Treatise, Volume One, 69–92. His Holiness the Dalai Lama raised and answered the objection that there appears to be four refuge objects in Tibetan Buddhism:
Those are the Three Refuges–Buddha, his doctrine, and the spiritual community. However, in Tibet it s said that there are four refuges–Lama, Buddha, doctrine, and spiritual community. A woman from Germany who was interested in Buddhism asked me with considerable amazement, “How is it that the lama is considered even greater than the Buddha? I cannot accept this. What does it mean?” I told her that she was right. For, actually the refuges are only three–Buddha, doctrine, and the spiritual community. The reason for separate consideration of the lama or guru, however, is that the lama is like a messenger from the Buddha, the one who at this point introduces us to the path. Furthermore, a fully qualified lama is the equivalent of a Buddha. Thus, even though there is a purpose for treating the lama separately, in fact there is no lama or guru not included among Buddhas or the spiritual community; there are only three refuges not four. Lamas who are not properly qualified are again another matter.
Dalai Lama, The Dalai Lama at Harvard: Lectures on the Buddhist Path to Peace. Translated and edited by Jeffrey Hopkins (Ithaca: Snow Lion Publications, 1988), 17-18.
 See Garma C. C. Chang, The Hundred Thousand Songs of Milarepa (Boston: Shambhala, 1999). For example, Milarepa sings, “When I meditate on the identity of manifestation and Guru/ Does my Awareness wander?” (ibid., 198).
 Losang Chökyi Gyältsen (Portland: FPMT, 2013), 28. Verse 44 reads,
You have the ten qualities suitable for one
To teach the path of those gone to bliss.
Lord of Dharma, representative of all conquerors,
Mahayana virtuous friend, I make requests to you.
Verse 41 reads,
Your vajra body is subject to neither birth nor death,
But is a vessel of the mighty king, unification;
Please abide forever according to our wishes,
Not passing beyond sorrow until samsara ends.
Ibid., 23. Elsewhere, Lama Zopa Rinpoche further delineates absolute from conventional or “ordinary” guru:
So, guru is Buddha, so there is, Buddha has absolute buddha and conventional buddha. Absolute buddha is dharmakaya, that’s the absolute buddha. So it’s the same, absolute guru and absolute buddha, just one. So here, guru is Buddha. Also the, in order to guide us which takes the form, which takes the ordinary form, definition of ordinary is having mistakes, taking ordinary form, manifest, taking ordinary form or manifest is the same, so ordinary form which definition is having mistakes, so it means having delusions, having suffering, having mistakes in the actions, so that’s the definition of ordinary, taking ordinary aspect or ordinary manifesting form, it means that. So showing these things.
Unedited transcript. See http://www.lamayeshe.com/article/chapter/absolute-guru-dharma-vs-samsaric-happiness
 Buddha nature may be divided into two types, naturally abiding and transformational. See the Dalai Lama, Harvard, 104–9.
 For a classic description of the exponentially escalating powers attained as the bodhisattva progresses from one bodhisattva path (ground) to the next, see Candrakīrti’s Madhyamakāvatāra. A partial translation (omitting the perfection of wisdom) is found in Hopkins, Compassion, and a complete translation in C. W. Huntington Jr. and Geshé Namgyal Wangchen, The Emptiness of Emptiness (Honolulu: University of Hawaii Press, 1989).
 See Tsongkhapa, Great Treatise, Volume One, 70–77, for details on how to examine the teacher’s qualities prior to wholehearted commitment.
 Dhargyey writes, “The Buddha’s action (’phrin-las, meaning ‘the act of delivering tidings’) is his manifestation of himself in physical forms, radiating peace and virtue in order to encourage others on the path…the manifestation taken depends on the type of beings at a particular time and place.” See Geshe Ngawang Dhargyey, Tibetan Tradition of Mental Development. Translated by Sharpa Tulku and Khamlung Tulku (Dharamsala: Library of Tibetan Works and Archives, 1974), 1992, 63.
 For an inspiring account of Gyalwa Ensapa’s own exemplary guru devotion that led to enlightenment in that lifetime, see Janice D. Willis, Enlightened Beings (Boston: Wisdom, 1995), 57–72.
 “Initiation” refers to tantric empowerments (dbang, abhiṣeka) pertaining to the vehicle of secret mantra (gsang sngags). Lung in this context refers to the practice of receiving a Buddhist text in the form of an oral transmission given by a qualified teacher who has themselves received the same from a qualified teacher. In this way the blessings of the transmission lineage are inter-generationally transmitted in unbroken fashion traceable back to the time of the Buddha or the time of the text’s composition/publication. To receive a lung in this auspicious manner is said to imprint the text on our mindstreams. Due to the force of such blessings, in the future one will be able to not only gain rapid intellectual understanding but also experientially penetrate the meaning of that text with clarity, accuracy and ease. Vasubhandu’s pigeon is a famous case in point:
The great Indian pandit, Vasubandhu, who composed the important text, the Abhidharmakoska, would recite it aloud every day. A pigeon that nested on the roof of his house used to hear him, and when it died, Vasubandhu used his clairvoyance to see where the pigeon was reborn. He discovered that it had taken rebirth down the road, and they agreed to put their son into the highly respected pundit’s care. The child–later known as Lobpön Loden (Acharya Sthiramati; Lodrö Denpa)–took ordination as a monk, became a great expert in the Abhidharmakosha, which he had heard so many times in his previous life as a pideon, and wrote several commentaries on it. This is another example of the great benefit that simply hearing Dharma teachings can bring.
Lama Zopa Rinpoche, Virtue and Reality (Boston: LYWA, 2008), 18. For a thorough account of the role of ritual transmission in the monastic setting, see Dreyfus, The Sound of Two Hands Clapping: The Education of a Tibetan Buddhist Monk (Berkeley: University of California Press, 2003), 155–57.
 Guru yoga (bla ma’i rnal ’byor).