We see in this passage that Orc and the Shadowy Female had drawn Urizen down into Generation where he entered the state Satan, the state which is opaque to the vision of the infinite. Enitharmon, her heart touched by the situation, visited the material world which was developing but returned to Los and Eternity at will.
The Female Space if it becomes created, rather than remaining a possibility, withers the perceptive abilities exercised in Eternity to the five limited senses through which only a fraction of Eternity is perceptible. The Female (material) Space appears infinite to itself although it is less than a speck compared to Eternity.
Satan brings the space into being and it becomes Canaan (an image of the ideal) the training ground for the return to Eternity.
Milton, PLATE 10 , (E 104)
"Then Los & Enitharmon knew that Satan is Urizen
Drawn down by Orc & the Shadowy Female into Generation
Oft Enitharmon enterd weeping into the Space, there appearing
An aged Woman raving along the Streets (the Space is named
Canaan) then she returnd to Los weary frighted as from dreams
The nature of a Female Space is this: it shrinks the Organs
Of Life till they become Finite & Itself seems Infinite.
And Satan vibrated in the immensity of the Space! Limited
To those without but Infinite to those within: it fell down and
Became Canaan: closing Los from Eternity in Albions Cliffs
A mighty Fiend against the Divine Humanity mustring to War"
The world of generation has been set in motion and humanity has been granted free will to fall or rise according to his limited perceptions of his light of truth.
Jerusalem, Plate 13, ( E 156)
(But whatever is visible to the Generated Man,
Is a Creation of mercy & love, from the Satanic Void.)
Jerusalem, Plate 42, (E 189)
"There is a limit of Opakeness, and a limit of Contraction;
In every Individual Man, and the limit of Opakeness,
Is named Satan: and the limit of Contraction is named Adam.
But when Man sleeps in Beulah, the Saviour in mercy takes
Contractions Limit, and of the Limit he forms Woman: That
Himself may in process of time be born Man to redeem"
Included in the merciful agenda to return man to Eternity, Eve is formed from Adam, the one becomes two. Duality becomes manifest in the flesh as man and woman. But the world of generation initiated by Adam and Eve would lead to the birth of Jesus the incarnation, spirit and flesh reunited.
Jerusalem, Plate 31 Blake's view is that with the appearance of Jesus, a man had been found to sacrifice himself for Satan and so redemption had been accomplished. However the message of forgiveness, self-sacrifice and Christ within, was subverted by the Female Will - materiality. So the world of generation came under the influence of the church of this world, and eighteen hundred years of Enitharmon's perverted joy ensued. Now the eighteen hundred years have become two thousand years and man has not yet claimed the gift that Jesus offers - oneness with God and brotherhood among men.