What are the main teachings of the Buddha? The teaching is that one should pacify one’s mind. So one should generate inner peace in one’s mind. Buddha taught three different gradual paths to help us realise inner peace within our minds. They are Hinayana, Mahayana and the Secret Vajrayana. This is all the different of Buddhist teachings brought into three special points.
So why is it necessary that the Buddha taught in three different ways or three different paths? He presented the teaching in such a way because sentient beings of the world have different types of mind, different characteristics. Some people have very open, vast minds, some people have a very closed type mind. For that reason the Buddha taught varying techniques, not just one. However, if one reaches the very end of any of the three paths, the result is the same, the final result is complete enlightenment.
Mingyur Rinpoche
source: https://www.samyeling.org/buddhism-and-meditation/teaching-archive-2/mingyur-dorje-rinpoche/three-vehicles-four-noble-truths/
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