Chapter 5

Chapter 5 comprises 3 parts. Many state that these parts are disparate, without any connection.
Let's see what it is about.

Quote

Heaven and earth do not act from (the impulse of) any wish to be benevolent; they deal with all things as the dogs of grass are dealt with. The sages do not act from (any wish to be) benevolent; they deal with the people as the dogs of grass are dealt with.

May not the space between heaven and earth be compared to a bellows?

'Tis emptied, yet it loses not its power;
'Tis moved again, and sends forth air the more.
Much speech to swift exhaustion lead we see;
Your inner being guard, and keep it free. (Legge version)

Commentary

The first part:
Sages (just like Heaven) don't practice benevolence as a matter of fact. They treat others as straw dogs meaning with impartiality, the same as performing a ritual. To say more, they show what time requires: benevolence as well as contempt. (1)

The second part is about the virtue of emptiness (2): it never exhausts and produces things continuously and unconditionally.

Part three:
Therefore it is futile to polemise on things and their characteristics as long as they (the things) share the same condition of emptiness, meaning missing of content. (3)

Finally, the sage rests in tranquillity (see also: About the state of stillness) or in the center/middle, meaning without parti pris.

Benevolence, learning and transformation are subjects matters of Confucius. Lao tzu teachings insist on the natural behaviour that opposes the Confucian doctrine.

Notes:
1. Straw dogs are artefacts created at the beginning of rituals. First, they deserve people's appreciation and respect. Upon the completion of the ritual, they are destroyed and people step on them with disdain.

2. Mystical void, the mother of ten-thousand equaled with the Tao. -> More about emptiness.

3. This concept is close to the Buddhist philosophy.
Regarding the Buddhist emptiness,, it refers to the observable fact that things and human beings are but a flux of energies and continuous transformation process, that is, nothing stable, fixed, rooted.

Concordance?

Ramana Maharshi: there's nothing outside the mind. And the mind must cease in order to seize the true Self.

Buddha: the form is void and the void is form.