The strong do what they can and the weak suffer what they must

This line comes from the famous Melian dialogue, in which a powerful Athenian navy besieges Melos. The Athenians thus speak from a position of power.

"...we shall not trouble you with specious pretenses---either of how we have a right to our empire because we overthrew the Mede, or are now attacking you because of the wrong that you have done us---and make a long speech that would not be believed; and in return, we hope that you, instead of thinking to influence us by saying that you did not join the Lacedaemonians, although they are colonists, or that you have done us no wrong, will aim at what is feasible...since you know as well as we do the right, as the world goes, is only in question between equal power, while the strong do what they can and the weak suffer what they must."

Melos attempted to argue from a "law of equality", of humanity at its best. Athens argued with reality. Melos, being weak, has no capability at all to discuss anything in equality.

Singapore, a small nation in a world full of sharks, believes in humanity at its best - that all small states should be equal with big states. But the nation is under no delusions of humanity. It is armed to the teeth militarily, has an outsized economy to fund that military, and has forged strong diplomatic relationships with both the western world and with China (but leaning more on the western world).

The Chinese themselves also remember the lessons learnt. 弱就要被挨打。