It is extremely difficult to obtain a human body. However, even being obtain a human body, very less of them hear the name of Buddha; after hearing the name of Buddha, only very rare of them have confidence; and even feeling of confidence, after they start going to hear dharma, many of them are still like a stubborn wild beast, destroy their samaya and vow, falling deep downward. Seeing all these sentient beings, bodhisattva feel unusual desperate. And I, Padmakara feeling infinitely sad.

-- Padmasambhava, Guru Rinpoche