Because, in ancient times, the cow was a kind of animal that people attached great importance to. Its personality is hard-working, working in the fields, without a trace of complaint. Therefore, in the eyes of people at that time, cattle played an important role in their lives.
Moreover, the cow's personality is very docile, and it is rare to see the cow lose his temper, but he works very diligently and meticulously. Therefore, the character of cattle is more in line with Taoist thought.
Although the horse is also very good, its character seems to be more Confucian. In order to be more in line with Taoist thought, Lao Tzu always rides an ox in people's paintings.
Secondly, why is it a green cow? Not a black cow or a white cow?
As for the color, it's not random selection and scribbling, but also exquisite. We all know that there are five planets in Jin Mu, water, fire and earth. In ancient times, these five planets were represented by five colors, and they represented the sons of five emperors.
The so-called five emperors are straight black, yellow, green, white and red, which symbolize five directions. Jupiter, also known as Di Qing, represents the emissary of the East.
Laozi is known as the sage of the East, saying that he comes from the East, so among the five colors, cyan suits him best.
A man from the East, riding a blue bull, is actually implying how great his wisdom and Taoist culture are and how far-reaching their influence is.
A saint from the east, riding a green cow, gradually walked to the west. It is such a painting that is gradually printed in everyone's mind. Later generations will draw Laozi according to this image when they draw Laozi again.