On the nature of things (books 1 - 3)   

Whereas, of truth, because all things exist,
With seed imperishable, Nature allows
Destruction nor collapse of aught, until
Some outward force may shatter by a blow,
Or inward craft, entering its hollow cells,
Dissolve it down. And more than this, if Time,
That wastes with eld the works along the world,
Destroy entire, consuming matter all,
Whence then may Venus back to light of life
Restore the generations kind by kind?
Or how, when thus restored, may daedal Earth
Foster and plenish with her ancient food,
Which, kind by kind, she offers unto each?
Whence may the water-springs, beneath the sea,
Or inland rivers, far and wide away,
Keep the unfathomable ocean full?
And out of what does Ether feed the stars?
For lapsed years and infinite age must else
Have eat all shapes of mortal stock away:
But be it the Long Ago contained those germs,
By which this sum of things recruited lives,
Those same infallibly can never die,
Nor nothing to nothing evermore return.
And, too, the selfsame power might end alike
All things, were they not still together held
By matter eternal, shackled through its parts,
Now more, now less. A touch might be enough
To cause destruction. For the slightest force
Would loose the weft of things wherein no part
Were of imperishable stock. But now
Because the fastenings of primordial parts
Are put together diversely and stuff
Is everlasting, things abide the same
Unhurt and sure, until some power comes on
Strong to destroy the warp and woof of each:
Nothing returns to naught; but all return
At their collapse to primal forms of stuff.
Lo, the rains perish which Ether-father throws
Down to the bosom of Earth-mother; but then
Upsprings the shining grain, and boughs are green
Amid the trees, and trees themselves wax big
And lade themselves with fruits; and hence in turn
The race of man and all the wild are fed;
Hence joyful cities thrive with boys and girls;
And leafy woodlands echo with new birds;
Hence cattle, fat and drowsy, lay their bulk
Along the joyous pastures whilst the drops
Of white ooze trickle from distended bags;
Hence the young scamper on their weakling joints
Along the tender herbs, fresh hearts afrisk
With warm new milk. Thus naught of what so seems
Perishes utterly, since Nature ever
Upbuilds one thing from other, suffering naught
To come to birth but through some other's death.

And now, since I have taught that things cannot
Be born from nothing, nor the same, when born,
To nothing be recalled, doubt not my words,
Because our eyes no primal germs perceive;
For mark those bodies which, though known to be
In this our world, are yet invisible:
The winds infuriate lash our face and frame,
Unseen, and swamp huge ships and rend the clouds,
Or, eddying wildly down, bestrew the plains