tao teh ching 76

A man is born gentle and weak.
At his death he is hard and stiff.
Green plants are tender and filled with sap[1].
At their death they are withered and dry.

Therefore the stiff and the unbending is the disciple[2] of death.
The gentle and yielding is the disciple of life.

Thus an army without flexibility never wins a battle.
A tree that is unbending is easily broken.

The hard and the strong will fall.
The soft and the weak will overcome[3].

[1] The Ma wang tui text has: When the ten thousand things and grasses and trees are alive, they're supple and pliant.
[2] Lau and the Ma wang tui both have 'companions'.
[3] Lau's version of these last four lines is:

Therefore the weapon that is strong will not vanquish;
A tree that is strong will suffer the axe.
The strong and big takes the lower position,
The supple and weak takes the higher position.

but the Ma wang tui version of the first two comes closer to the Gia–fu Feng reading.

Wang Pi says:

If one inflicts violence on all under Heaven through the use of stiff ('powerful') military force, one will be despised by the people. Thus one will surely fail to enjoy victory.
A stiff tree will be attacked by all sorts of creatures.
When the strong and great are below, this is the trunk of the tree.
When the soft and pliant are above, this refers to the branches.

Professor Cheng's commentary is: The stiff and the hard are moribund, the soft and supple vital. If an army is strong it will not be victorious; a hardy tree gets the axe. The stiff and hard trunk is below and the soft and supple branches above. This accords with the laws of nature.

What is 'strong' is one's resolve not to be taken in by appearances; what is 'weak' is the suppleness of allowing things to be as they are and then to dissolve.