By seriousness frivolity can have a root.
By calm impatience.can have a master.
Thus the nobleman travels all day long
never leaving the heavy wagons.
Although one have a thriving monastery,
a swallow’s nest is superior.
To what avail is it to be master of ten thousand chariots
if, here in the land under Heaven, one act in a reckless manner?
By frivolity, one loses the root.
By impatience, one loses the master.
Evidently, this is a passage about maintaining calm and restraining frivolous or reckless, hotheaded or impatient actions.
It includes the observation that such rashness can easily come over one when one feels powerful. In particular, it alludes to the general, the abbot and the emperor. The general does well to act with circumspection and not leave his baggage train to go chasing after wild adventures or risky skirmishes. The abbot might start to feel superior if his monastery is thriving, but should remember that his achievement is less than that of a swallow who also builds a fine nest. The emperor, similarly, may have a thousand chariots at his command, but if he acts in a childish manner unbefitting his station, even he loses influence and effectiveness.
The middle lines are open to a number of translations and different authorities have taken them in different ways, but I think that the reference to the swallow is probably the original meaning of the character and it is apt. The swallow is a symbol of good fortune in Chinese mythology. The birds have great skill in flying and however far they go they always return. The pairs cooperatively build a fine nest and so offer an example of family life. In a peaceful and settled village, there are likely to be many swallow nests and the arrival of the birds in the spring indicates improved weather and the start of the season of growth and new life. It is characteristic of the philosophy of the Tao Te Ching to show how human efforts fall short of those of Nature. The abbot can, therefore, keep himself humble by reflecting that even his best efforts will never match those of the luck-bringing birds.
The last couplet has a hint of the idea that recklessness is a matter of losing what is below - the root - while impatience is a matter of losing what is above - the head.
This passage does not mean that frivolity, recklessness, impatience and so forth should be extinguished completely so much as that there should also be something solid in a person that avoids things going too far. This is especially true for people who hold much authority and responsibility. The Tao Te Ching can be taken as a manual of advice to such people. If one is in such a position, many people rely upon one and one cannot, therefore, afford to let ordinary passions go too far or it brings disaster not only for oneself but for many others. Here in the land under Heaven, one must take some responsibility and accord with realities.
The ruler or person of responsibility, therefore, needs to cultivate calm and keep in mind the seriousness of his or her position, the consequentiality of words and deeds. Generally this means acting with caution and “not going too far from the baggage train”. This latter notion is taken from the image of an army in ancient times that would be followed by a baggage train. The soldiers can move faster than the oxen, but are wise not to go too far and risk getting cut off from their essential supplies. The general must also consider that if he is lost the whole army will be in trouble and so he has a special responsibility to be careful. This is a bit like the case of social insects. The hive depends upon the queen bee. The anthill depends upon the queen ant. The queen therefore stays in the deepest recess of the colony.
So there is something here about the weight of responsibility and the restriction it imposes. Taoists often avoided high office for precisely this kind of reason. They preferred to be like the swallow flying freely than to be like the prestigious abbot who must be serious and calm the whole time.