Hi there, this is from page 22 of Trijang Rinpoche's commentary Music Delighting an Ocean of Conquerors which can be downloaded from the home page of this web site:
Best wishes
Robert
"Great beings, after attaining the state of unexcelled transcendent wisdom that is the culmination of the qualities of abandonment and realization, the Dharmakaya that is said to be the fulfillment of their own welfare, for the sake of others, display their body and speech in accordance with the aspirations of trainees. This variegated display merely appears to be distinct forms but in actuality is not separate from the great bliss expanse of Dharmakaya. Any Buddha is the base of all emanations so there is no need to be narrow?minded thinking that a certain emanation is one particular Buddha's emanation and could not be the emanation of another. Also, it is quite possible that some who have not studied the scriptural tradition or have studied but without much discerning wisdom, might think that as long as the successive incarnations of a lama live at different times it is fine, but it is impossible for two of their incarnations to be alive simultaneously. In fact, it is not a problem because, as is said in Sutralankara,
Just as immeasurable rays of the mandala
Of the sun all mix together,
Always engaged in the same work,
That of illuminating the world,
Likewise in the stainless sphere,
Innumerable Buddhas mix together,
Engaged in the same deeds,
Illuminating transcendent wisdom.
Thus, many sunrays mixed together all function to open lotus blossoms and so forth. Similarly, the inconceivable deeds of body, speech, and mind, the three secrets of the Buddhas are all said to be engaged in the same activity of ripening and liberating trainees. The same sutra says,
Pure rivers, without going under the earth
In separate places, with separate waters,
In small amounts, function separately,
Providing slight support for water life.
Yet when they all reach the ocean,
Their abode is one, and one great body
Of water acts as one, and always supports
Great quantities of marine life.
Those who have not yet attained Buddhahood
Have separate bodies and intellects,
Little realization and do separate work,
Always providing for the welfare of few sentient beings.
All those who abide in Buddhahood itself,
Have one form and one great realization,
And their deeds, all mixed together,
Always support great hosts of beings.
For example, rivers, without going underground, are separated in different pools and channels. They remain apart, have little effect, and provide only a small habitat for creatures. But once they cut down through the earth and reach the salt water of the sea, they all become one habitat, one great body of water, of the same salty taste, act as one, and always support vast amounts of life. Likewise, the stable Bodhisattvas who are not abiding in, have not attained, complete enlightenment, their bodies and sense of self are different, they are of different levels of faculties, their realizations are small and activities separate so that they benefit few sentient beings. Once they abide in Buddhahood itself, their form is one unimpeded transcendent wisdom, their realization is extremely vast, there is no difference in their faculties, and their actions all merge as one to always benefit great hosts of beings.
In brief, Buddhas only appear different to trainees, but they are actually of one taste in stainless Dharmakaya. All vehicles, both the common and uncommon, are in agreement on this. It is not only Buddhas who take on many various forms for trainees from a single base of emanation. Even Bodhisattvas abiding on the first ground, the Joyous, in the period subsequent to their direct realization of emptiness called subsequent attainment, can see a hundred Buddhas in an instant, know their blessings, and abide for a hundred eons knowing the origins and ends of each. They can enter and arise from a hundred different states of meditative equipoise in an instant. They can move a hundred worlds and are capable of illuminating them all, ripening hundreds of sentient beings in an instant through miraculous emanations. Hundreds go to the state of Buddhahood and they open hundreds of Dharma doors in an instant. They can emanate a hundred forms from their body in an instant with hundreds of Bodhisattvas in attendance on each. Thus attaining these twelve sets of abilities one hundred fold, if, at that point they are able to emanate hundred of different forms, what need to mention the capacity for emanation of those great beings who have exhausted all defects and perfected all possible qualities completely! Furthermore, there is no contradiction in there being multiple incarnations of a single holy master. As said in the extensive biography of Je Tsongkhapa by Gyalwang Choje,
Therefore, what is the contradiction in the incarnation of one holy being appearing in the list of incarnations of another holy being? Those holy beings are not incapable of more than a single emanation! For instance, in terms of Tibet being the field to be subdued by Arya Avalokitesvara, many of the previous and present great beings were Avalokitesvara himself. We see or hear of the lists of their incarnations merging at times and who can say that one of them is wrong? With this insight, one is freed from the bondage of doubt arising from deluded analysis and prejudice, and develops a pure view of all holy beings impartially.
Thus, in the case of this great being's incarnations, there are many different lists, and it would not be possible to tell the stories of all of them. Here, I will just give a rough account of the incarnations mentioned in the praise. A brief account of Manjusri has already been given. For more details of his common and exclusive biographies, please consult the many that appear in both the Sutras and Tantras."