《太上内丹守一真定经》

With reverence one hears that, at the beginning of the great Dao (the Way), primordial chaos began to differentiate, and Heaven and Earth were thereby formed; the sun and moon moved in alternating courses, and the Jing (essence) and Qi (vital energy) of Yin-Yang joined with one another. From this the great Dao transforms and gives birth to the myriad things, and it can also protect and nourish life and regulate the bodily form. People of the world do not understand these principles; they sink into greed and desire, and instead harm life and shorten the span of years. Now that this sacred teaching is being transmitted, you ought to cultivate it with reverence.

The Supreme Lord of the Primordial Beginning (a revered deity of Daoism) told the various Zhenren (Perfected) who were just beginning their studies: I possess a subtle method of the Dao that has long been kept secret and not transmitted. When it moves and divides into two, that is Yin; when it is still and guards the One, that is Yang. Yin and Yang transform without fixed constancy, yet guarding the One enables one to hold fast to the root. When one understands and realizes the constant Dao and embraces the primordial One, the spirit becomes clear and bright. If you wish to preserve and nourish life for a long time, you should ingest and refine the “golden crystal” (the essential Qi in the practice of Neidan, internal alchemy). Settle the mind and Shen (spirit), regulate the breath, and make the true breath continuous and unbroken; by guarding it in this unbroken way, one enters a realm that is hidden, subtle, and mysterious.

In the Middle Field (one of the Dantian, energy centers, spoken of in the Neidan cultivation of the human body), the true fire flows; the Yin soul rises to meet it; Kan and Li (symbols of water and fire) blend and become firm, and transformation then occurs of itself. The root of cultivation lies in entering settled concentration, and therefore it is called the “numinous root.” When cultivation is accomplished, the light becomes vast and radiant and of itself can illumine Heaven and Earth; the “green intestines and elixir marrow” (a way of speaking, in Neidan, of the transformation of Jing and Qi within the body) are preserved and endure for ten thousand generations. When Yin Qi recedes and Yang Qi becomes pure and complete, one can ascend in broad daylight.

The Great Lord of the Dao of the Jade Empyrean (a revered deity of Daoism) then said: This is a treasure within the body, and also the source of the myriad Qi. When you obtain this source, the six functions arise from it. You should ponder its principle with concentrated thought and guard the true state of settled concentration; in this way, form and Shen naturally become wondrous together, unite with the Dao, become of the same kind as Heaven and Earth, and reach a realm of incomparable vastness.

At that time, after the various beginning Zhenren had heard this subtle method of the Dao, they withdrew to quiet chambers, devoted themselves to still contemplation, returned to the Great Beginning (the primordial state before the myriad things had differentiated), and in the end accomplished the Dao of ultimate perfection.