Anger may in time change to gladness; vexation may be succeeded by content. 21. But a kingdom that has once been destroyed can never come again into being; nor can the dead ever be brought back to life. 22. Hence the enlightened ruler is heedful, and the good general full of caution. This is the way to keep a country at peace and an army intact.

But a kingdom that has once been destroyed can never come again into being; nor can the dead ever be brought back to life.

No ruler should put troops into the field merely to gratify his
own spleen; no general should fight a battle simply out of pique.
If it is to your advantage, make a forward move; if not, stay
where you are.
Anger may in time change to gladness; vexation may be succeeded
by content.
But a kingdom that has once been destroyed can never come again
into being; nor can the dead ever be brought back to life.

"Liberty may be gained, but can never be recovered." (Bk2:8)

...Cities may be rebuilt, and a People reduced to Poverty, may acquire fresh Property: But a Constitution of Government once changed from Freedom, can never be restored. Liberty once lost is lost forever. When the People once surrendered their share in the Legislature, and their Right of defending the Limitations upon the Government, and of resisting every Encroachment upon them, they can never regain it.

That is not dead which can eternal lie,
And with strange aeons even death may die.

A government should not mobilize an army out of anger, military leaders should not provoke war out of wrath. Act when it is beneficial to do so, desist if not. Anger can revert to joy, wrath can revert to delight, but a nation destroyed cannot be restored to existence, and the dead cannot be restored to life.

Is it possible to become ecstatic amid destruction, rejuvenate oneself through cruelty?

Nothing is ever really lost, or can be lost, / No birth, identity, form - no object of the world. / Nor life, nor force, nor any visible thing;... / The body, sluggish, aged, cold - the embers left from earlier fires, / The light in the eye grown dim, shall duly flame again

Anger will never disappear so long as thoughts of resentment are cherished in the mind. Anger will disappear just as soon as thoughts of resentment are forgotten.

Just as there are laws of Conservation of Matter and Energy, so there are in fact Laws of Conservation of Pain and Joy. Neither can ever be created or destroyed. But one can be converted into the other.

The time that has gone with happiness does not come back with grief, and nothing the future may bring can wither a day or wipe out an hour in the life that has been lived.

Sensual pleasure passes and vanishes, but the friendship between us, the mutual confidence, the delight of the heart, the enchantment of the soul, these things do not perish and can never be destroyed.

There is no memory that time does not efface, no pain that death does not destroy.