Chapter fourteen, from Treasure of Wish-Fulfilling Gems: A Textbook of Universal Vehicle Precepts, by Kunkyen Longchen Rabjam, (p. 119 Essential Tibetan Buddhism)

Life's Impermanence

Got Enlightenment? - 1
Got Enlightenment? 
Dalai Lama Poster
Gursky, Jason

Once acquired, this precious life with liberty and opportunity
Has the characteristics of instantaneity, impermanence, and decay. 
The three realms are deceptive and illusory in nature.
Though beautified by the wealth of its four continents,
Our earthly environment is impermanent and exhibits decay.

Even this body should be recognized as a ball of foam,
Like those of all these beings now on earth.
In a hundred years, they will certainly not be,
Since everything born eventually dies.
Just as your own life span will come to an end,
In places like markets, crossroads, guest houses,
All these crowds of diverse beings will be scattered.

Contemplate the certainty from the heart that your relations
And the resources of your amassed possessions,
Like a city deserted, will come to nothing.
Since whatever wealth one has amassed
Is impermanent and without essence, you should be detached;
You ascend to the wealthy cities of paradise,
Even as you go beyond death and fall into miserable lives.

Be sure that pride in this life or wealth grants no equanimity,
Since one is separated in time from things outer and inner.
Since impermanence and death are certain,
Give up on the delusion of permanence.

Thich Nath Hanh, I Have Arrived
Thich Nath Hanh,
I Have Arrived

Subatomic matter endures momentarily,
Being impermanent as a flash of lightning,
So you should realize ultimate truth just as quickly.
The variety of habitats and life-forms is transient,
Essenceless as an illusion of a banana tree,
Therefore this life-cycle is called impermanent,
And clinging to one's self or work is not acceptable. 

Habitats and beings are made of four elements, subject to decay.
Embodied beings vanish like transient settlements.
Since compounds are everywhere, nothing at all is permanent.
Nothing in life is certain but that death is never partial.

So one must contemplate from the heart death's certainty.
Since, at the time when death comes, home and possessions, 
Friends, the company of celebrated experts, and so forth
Are no company at all, you must realize ultimate truth.

One's perception of markets, riverbanks, miraculous trees,
Thunderheads, the movements of living beings, moon and sun,
Impermanent and transient, will likewise suddenly cease.
At the time of death, your best friends are your stores of virtue;
So rely on the ultimate, and strive to realize its essential meaning.

On the path of analysis, one must be ever mindful of death.
Measure your practice by watching the compounded decay.
With effort, abandon the fears and activities of this life,
Not resting in the ordinary even an instant.

Develop a renunciative, repentant mind of few diversions,
For the benefits and virtues of such a mind are infinite.
Eliminate worldly faults and naturally gather virtues.

Free from the permanence habit, stop enmity and kinship, desire and hate,
Be diligent in virtue, and know this life as deceptive.
Fully gather both stores, and the gods will see you as glorious,
You will ascend to the heavens, achieve lifetimes of bliss,
And quickly earn the state of enjoying the elixir of immortality.