Here's a quote for the day. This is from the Yin Shu (引書), the "Book of Pulling." It is the earliest known book we have so far on Daoyin (i.e., early versions of Qigong) dated to c. 186 BCE. It was unearthed at Zhangjiashan in the early 1980s. This is the first line of the text, and those of you who've studied the Neijing will recognize this as a variation on a very important line(s) in that text.
春產，夏長，秋收，冬藏，此彭祖之道也
Spring births, summer flourishes, autumn harvests and winter stores. This is the Way (i.e., Dao) of Peng Zu.
For those who aren’t familiar with Peng Zu, he was a mythical figure in classical Chinese philosophy who lived several centuries. In the Neijing (those of you who've studied the Neijing will recognize this as a variation on a very important line(s) in that text) we see this from Ling Shu Chapter 44:
春生, 夏長, 秋收, 冬藏, 是氣之常也, 人亦應之
Spring engenders, summer flourishes, autumn harvests and winter stores. This is the constant of Qi and humans also resonate [with this movement].
Clearly these lines are related, and this was a common and essential concept in medicine during the Han period. Being included in the Yin Shu also means that it was essential to cultivation practices, which is why it is the Dao of Peng Zu (i.e., the Way of cultivating health and longevity). Here we see the movement of the Five Phases at their most essential, and all aspects of medicine and cultivation must be based on this.
So, when you next practice Qigong, pick up an acupuncture needle, or write an herbal formula, think of this idea and evaluate if you are working in this grand cycle of life.