Ching-yuan Wei-hsin, a Chinese Ch'an master, once said this:
Thirty years ago, when having not studied Ch'an, this monk saw mountain was mountains and water was water.
Later, when following the good teacher's guide, this monk...
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to the group in the Deer Park near Varanasi, the Buddha spoke of the Four Noble Truths. The Four Noble Truths sum up, in a systematic formula, the central teaching of the Buddha.