Blake's Death

For Blake the word, death, had many meanings:

1. Physical death:

Quoting Damon p. 99: 

"Death of the physical body is the shedding of the shell (garment, robe) which the soul, or spiritual body has grown for protection in this world.  It's the return of the soul to Eternity.  It is an episode of life, a state through which one passes, awakening to Eternal life (J 4:1-2)".

Blake indicated the nature of physical death, particularly of his brother, Robert's death in a letter (9) to Hayley he wrote:

      "Thirteen years ago. I lost a  brother & with his spirit  I  converse daily & hourly in the  spirit. & See him in my

remembrance in the regions of my  imagination.

I hear his advice & even now write from his  Dictate--"

2. For Blake Eternal Death, itself seemed to have many meanings:

Among other things it seems to concern Ulro and the Spectre. Looking at The Four Zoas we read:

"There is from Great Eternity a mild & pleasant rest
Namd Beulah a Soft Moony Universe feminine lovely 
Pure mild & Gentle given in Mercy to those who sleep
Eternally. Created by the Lamb of God around
On all sides within & without the Universal Man
The Daughters of Beulah follow sleepers in all their Dreams
Creating Spaces lest they fall into Eternal Death                

The Circle of Destiny complete they gave to it a Space
And namd the Space Ulro & brooded over it in care & love
They said The Spectre is in every man insane & most
Deformd     Thro the three heavens descending in fury & fire
We meet it with our Songs & loving blandishments & give          
To it a form of vegetation But this Spectre of Tharmas
Is Eternal Death What shall we do O God pity & help"

(The Four Zoas [Nt 1], 5.42; E303)  

Elsewhere in  Milton 4.15; Erdman 98 he reported this
conversation between Los and Satan:

"Satan was going to reply, but Los roll'd his loud thunders.

Anger me not! thou canst not drive the Harrow in pitys paths.
Thy Work is Eternal Death, with Mills & Ovens & Cauldrons.
Trouble me no more. thou canst not have Eternal Life

So Los spoke! Satan trembling obeyd weeping along the way.
Mark well my words, they are of your eternal Salvation"

Satan and the Spectre of course are synonymous. 

"And Milton said, I go to Eternal Death!" 

If you get the picture Milton, in Heaven, choses the path the 
Savior trod; he incarnated; he came down from Heaven into
Earth and for a similar purpose.  But here the meaning of 
Eternal seems very clearly mortal life.
There are many other instances of the words in Milton.

Turning to Jerusalem Blake makes it pretty clear in Plate 4:
"Of the Sleep of Ulro! and of the passage through
Eternal Death! and of the awaking to Eternal Life."
It would be very worthwhile to read this plate carefully. 
The last occurrence of Eternal Death in Jerusalem occurs in 
Plate 98 lines 21-24:
"Driving outward the Body of Death in an Eternal Death &
     Resurrection   
Awaking it to Life among the Flowers of Beulah rejoicing in Unity
In the Four Senses in the Outline the Circumference & Form, for
     ever
In Forgiveness of Sins which is Self Annihilation." (E257)
 
(I wonder if he was thinking of Romans 7 when he spoke of the 
Body of Death.  The forgiveness of sins is Self Annihilation, the 
end of mortal life.)