Finding in the Nature of Mind (Dzogchen)

Dzogchen at its core is similar to Zen, so I thought I'd post an important section from a historic Tibetan master, Longchenpa.  This passage is from one of his most famous works, "Finding Rest in the Nature of Mind"

Chapter 10, Sections 1 - 10:

1. The practitioner who thus unites
The generation and perfection stages
Gains entry to the unborn, empty nature of phenomena.

2. Now all phenomenal existence,
All the things of both saṃsāra and nirvāṇa,
Are from the outset without self
And are beyond conceptual construction.
Through ignorantly clinging to them,
Beings wander in existence.
Saṃsāra and nirvāṇa, various joys and sorrows,
Do indeed occur.
Yet in the very moment of arising,
They are empty in their nature.
Know that they are like illusions.
Know they are like dreams.

3. Though all the things appearing outwardly
Occur within the mind, they are not the mind itself,
But neither are they something other than the mind.
Although by force of habit there may seem to be
Duality of apprehender-apprehended,
In the moment it occurs,
This duality has no reality.
It is like a face and its reflection in a mirror. 

4. Although a face appears upon the surface of the mirror,
It is not there.
And yet no other thing
Has cast its form upon the glass.
While not being there, its likeness there appears
And is perceived as different from the mirror.
Know that manifold phenomena are all like this.

5. If left unexamined, things are quite convincing,
But when they are investigated, they become elusive.
When thoroughly examined, they transcend
All speech, all thought, all formulation.
Whether as existing or as not existing,
There’s no finding them.
Neither are they beyond, nor are they not beyond,
The ontological extremes.

6. It is in the manner of illusion
That their arising and their dwelling
And their ceasing all appear.
But from the very instant they occur,
This same arising and the rest have no intrinsic being.
They are like the water of a mirage
Or the moon reflected in a pool.

7. In particular, the six impure migrations
Appear but have no true existence.
They are deceptive forms, the products of habitual tendencies,
Like falling hairs that those with visual ailments see.
And just as those who wish to be restored
Must purify their phlegm,
In just the same way, those who wish to dissipate illusion
Must clear away the cataracts of ignorance.

8. The antidote for this is self-cognizing primal wisdom.
By this means you come to clear conviction
Of the empty nature of saṃsāra and its habits.
And you know with certainty
That what is empty does appear.
You understand the nonduality
Of appearance and emptiness,
And thus you know the sense of the two truths.
By dispelling both extremes and striving for the middle way,
You come to freedom in the sky-like state,
Abiding neither in existence nor in peace.
This is ultimate reality sublime and quintessential:
The fundamental nature of the Natural Great Perfection.

9. Appearance in itself does neither good nor harm,
But clinging to appearance binds you in existence.
Thus there is no need to search through manifold appearances.
Just cut the root of mind that clings to them.

10. The mind does seem to be and yet lacks real existence.
When searched for, it’s not found;
When looked for, it’s not seen.
No color does it have, no shape; it cannot be identified.
Not outside or within; throughout the triple time,
It is not born, it does not cease.
And it is not located anywhere on this side or on that.
Groundless, rootless, it is not a thing.
There is no pointing to it: mind is inconceivable.