Verse 6

6. He is the unthinkable,  unmanifest,  of endless forms,  the good,  the peaceful,  Immortal,  the origin of the worlds,  without beginning,  middle,  and end,  the only one,  all-pervading,  Consciousness,  and Bliss,  the formless and the wonderful.

"He is the unthinkable".

The Absolute is in fact "yourself".  You are the Absolute because the Absolute is all this very Existence.  Through the delusion of Maya there is an experience within consciousness of duality and a "self",  nevertheless there is but one Consciousness so the experience in consciousness of a thinking "self" is in reality merely a projection by the Absolute "Self".
This means that the projected experience of a "self" thinking cannot logically encompass that "Absolute Self" that projects that very thinking experience.
Therefore the Non-Dual Absolute ItSelf cannot be truly examined by the duality of thought,  the Absolute is  "unthinkable".

It is for the above reason that any meditation practice that might transcend Creation to experience the Absolute would be effectively delayed so long as it slips into desire and thinking.

"unmanifest".

The Absolute is the "unmanifest" primal singularity that is knowledge and consciousness absolute.  All that is manifest is merely a projection of that "unmanifest" knowledge made manifest in Consciousness.
Therefore all that is manifest is the Absolute but the Absolute is greater than all this that is manifest,  therefore the Absolute Itself is "unmanifest".

"of endless forms".

As stated above all that is manifest,  which is this universe,  is the Absolute itself.  This universe consists of name and form only and is made manifest from the infinite knowledge that is the Absolute.
The Absolute is infinite knowledge therefore "of endless forms".

"the good".

"the good" taken literally assumes the duality of good and bad,  but in reality good and bad do not exist as duality does not exist.
The meaning here is to remind us that the absolute Alone exists so what "IS" is all there is therefore what "IS" is what is meant to be or correct or good or all that can be or simply the Absolute Alone.

"the peaceful".

"peaceful" means free from disturbance.  Because the Absolute is the primal singularity of existence there literally is not another to cause disturbance.  The absolute itself is unmanifest,  it is the unmoving completeness of truth consciousness and bliss.  "the peaceful".

"Immortal"

The Absolute is immortal due to being without origination,  unborn.  Never changing state the Absolute is eternal.

"the origin of the worlds"

Being without origination the Absolute is the primal singularity of existence.  From that non-dual singularity all that is apparent now,  the universe with its worlds and so forth,  must have its origin and support within that singularity. 

"without beginning,  middle,  and end"

As stated above the Absolute is without origination and immortal,  meaning this One is without dimensions.

"the only one"

Existence being this primal non-dual singularity literally means the Absolute Alone Exists,  the only One,  there is no other.

"all-pervading"

Whatever exists is pervaded completely by Existence.  The Absolute is Existence Alone therefore is all pervading.

"Consciousness,  and Bliss"

The Absolute being "the origin" of all things it consists of all knowledge.  The Absolute being absolute knowledge alone is therefore pure Consciousness,  with the harmony of completeness this Consciousness is transcendent Bliss.

"the formless and the wonderful"

Absolute Knowledge and Consciousness is without form.  The wonder of the Absolute is that although it is unknowable the wise can come to know of it.

Acknowledging the unreality of Creation through renunciation the Solitary sage meditates to open the heart and intellect to the indefinable unmanifest Absolute Truth.
To a casual observer the meditating Sage might appear to have abandoned life and purpose.  But to the wise he has found,  realised and now rests in Reality Alone,  the One immortal unity of Truth Consciousness and Bliss.