From a talk given by His Eminence Kalu Rinpoche in Darjeeling, India. Translated by Harold Richards.
The Buddha said that many hundreds of Dharma traditions would come into this world. All traditions would arise from the perfect action of awakened buddhas and would be their means of helping sentient beings. What would these means be like? Entrusting ourselves to some religious traditions would enable us to take birth in the elevated planes of those religions: as human beings or as desire realm celestial beings. Through entrusting ourselves to others, we could be born into the seventeen planes of the form realm or in the four states of the formless realm. Moreover, they reveal ways of blocking the access to ill-gone states (as animals, etc.) and gaining elevated planes of existence. All give us strength and transforming powers.
Some practices are meant to give us the capability of attaining Lesser Vehicle levels of the Enemy Conqueror and the Solitary Realizer (Hinayana arhat and pratyekabuddha) and others give the ability to reach the Greater Vehicle (bodhisattva and Buddha). They do this, and so I believe in all religious traditions. All derive from the perfect actions of the Buddha and give sentient beings release from cyclic existence in both temporary and ultimate senses. Accordingly, these are the subjects I teach my disciples.
While I was in Tibet there were eight major Buddhist traditions, but nowadays in India, the Land of Superiors, only four have been able to flourish. These are Sakya, Gelug, Nyingma and Kagyü. Again, each conveys the stainless word of the Buddha above all and has produced successions of expert scholars and realized saints (pandit and siddhalabdha) to further it.
Thus each is like pure gold, authentic Dharma untainted by anything vile, a thing most people don’t find even when they search, something that can lead to liberation from cyclic existence and to omniscience. This is Dharma in all its profundity and vastness.
If they are all the Dharma of the Buddha, why are there all these different systems? Generally speaking, the variety is produced according to the inclinations of different people. Each particular system is distinctly for the aptitudes of particular people whose minds are ready to be cultivated by such a system.