In the 28th Sarga of the Vairagya Prakarana of Yoga Vasishta, Lord Sri Rama is explaining the impermanent and ever-changing nature of the world to Sage Vishwamitra.
This world is either a falsehood or at least impermanent.
The huge valley, tomorrow a mountain will stand in its place.
The mountain, tomorrow it will be plain flat ground.
The body which today is adorned by silk clothes and expensive perfumes will tomorrow lie decaying in some distant pit.
The man who today is a celebrity will tomorrow be just a potful of ash.
The forest today will become a desert tomorrow.
The barren desert today will become a prosperous luxurious city tomorrow.
Not just these.
The tender child becomes a rough and tough youth after some time.
Then he becomes a weak ailing old man.
The glamor goes away.
The fanfare goes away.
The power goes away.
The wealth goes away.
The position goes away.
The powerful police officer retires, and he becomes just another ordinary man.
The world looks attractive, it is fascinating at times.
But it is like watching a beautiful dancer in a show.
She disappears when the show is over.
Your relationship with her is only for that much time.
This world is also like that dancer.
The fascination towards the world is momentary.
Or they are a few episodes that are momentary.

We have seen so many great empires vanishing.
Some of them, we don't even hear about them anymore.
They are not even there in the memory.
We will also be gone after some time.
Then, we will be there only in the memory.
After some time, even that memory won't be there.
In the world around us, new objects, beings, and events are appearing every day while the old ones are disappearing.
Humans die and are reborn as animals.
Animals die and are reborn as humans.
Even the celestials are cursed and become animals or trees or stones.
Nobody has freedom.
Even Brahma, Vishnu, and Rudra have to follow the flow of time.
Everything is destroyed at some point of time.
In no time, a beggar becomes wealthy.
In no time, a rich man becomes a beggar.
The wise man doesn't get carried away by the fancy of what he sees around him.

The sky is sometimes blue and calm.
Sometimes, it is filled with dark clouds.
Sometimes it scares you with thunder and lightning.
Sometimes, it is silver in color, sometimes it is beautifully red.
It keeps on changing.
The world around you is also like that.
It keeps on changing.

Sometimes, dangers come out of nowhere.
Sometimes prosperity and comforts come out of nowhere.
Nothing is permanent in this world.
Even our perspectives, states of mind, emotions are not permanent.
Sometimes the strong get defeated by the weak.
Sometimes, a crowd kills a man.
Sometimes, a single man kills a crowd.
The mind sees something and becomes happy.
The next moment it sees something else and becomes sad.
A man who is feared today is ridiculed tomorrow.
How can you trust such a world, asks Lord Rama.