This is from page 91 of Fearful Symmetry:
"Inspiration is the artist's empirical proof of the divinity of his imagination; and all inspiration is divine in origin whether used, perverted, hidden or frittered away in reverie. All imaginative and creative arts, being eternal, go to build up a permanent structure, which Blake called Golgonooza, above time, and, when this structure is finished, nature, its scaffolding, will be knocked away and man will live in it. Golgonooza will be the city of God, the New Jerusalem which is the total form of all culture and civilization. Nothing that the heroes, martyrs, prophets and poets of the past have done for it has been wasted; no anonymous and unrecognized contribution to it has been overlooked. In it is conserved all the good man has done, and in it is completed all he hoped and intended to do. And the artist who uses the same energy and genius that Homer and Isaiah had will find that he not only lives in the same palace of art as Homer and Isaiah, but lives at the same time."
Perhaps Blake is even more inclusive in this passage about Los' work: Jerusalem, Plate 13,(E 157) "Golgonooza: Los walks round the walls night and day. He views the City of Golgonooza, & its smaller Cities: The Looms & Mills & Prisons & Work-houses of Og & Anak: The Amalekite: the Canaanite: the Moabite: the Egyptian: And all that has existed in the space of six thousand years: Permanent, & not lost not lost nor vanishd, & every little act, Word, work, & wish, that has existed, all remaining still In those Churches ever consuming & ever building by the Spectres Of all the inhabitants of Earth wailing to be Created: Shadowy to those who dwell not in them, meer possibilities: But to those who enter into them they seem the only substances For every thing exists & not one sigh nor smile nor tear, Plate 14 One hair nor particle of dust, not one can pass away."Satan's Watch-fiends Never Find the Gate of Los
Jerusalem, Plate 35 , (E 181)
"this gate cannot be found
By Satans Watch-fiends tho' they search numbering every grain Of sand on Earth every night, they never find this Gate. It is the Gate of Los. Withoutside is the Mill, intricate, dreadful And fill'd with cruel tortures; but no mortal man can find the Mill Of Satan, in his mortal pilgrimage of seventy years"