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William Blake was a Romantic poet, and his writing was a reflection of his reactions to the world around him. Because of a mystical "encounter" Blake experienced as a very young man, his work often exhibits an "other-worldliness." As a Romantic poet, among other things, he had a strong respect for nature, and so, too, experienced a powerful personal reaction to the Industrial Revolution, looking forward to a land that was not poisoned by industry:
Blake hated the effects of the Industrial Revolution in England and looked forward to the establishment of a New Jerusalem 'in England's green and pleasant land.'
An example of a poem by Blake that reflects this is "Jerusalem." In this piece of writing, Blake reflects upon ancient days where feet traveled on England's "mountains green" and "pleasant pastures," showing Blake's regard for nature.
And did those feet in ancient time
Walk upon England's mountains green?
And was the holy Lamb of God
On England's pleasant pastures seen?
Next, God is referred to as "the Countenance Divine." The "satanic mills" refer in general to the Industrial Revolution, and the clouds are the outpouring of smoke hovering over the mills. "Jerusalem" symbolizes Blake's vision of humanities freedom from "commerce, British imperialism and war."
And did the Countenance Divine
Shine forth upon our clouded hills?
And was Jerusalem builded here
Among these dark Satanic mills?
The third stanza finds Blake preparing for a symbolic war: calling for his "weapons," including a "bow of burning gold." (Gold was not only valuable, but perhaps seen as the purest—maybe the "holiest"—of all metals.) And Blake gathers other figurative tools of battle: arrows of desire (raging intent), a chariot of fire, and a spear, and then he commands the clouds to "unfold."
Bring me my bow of burning gold!
Bring me my arrows of desire!
Bring me my spear! O clouds unfold!
Bring me my chariot of fire!
Lastly, Blake promises that he will not cease his mental fight. "Blake's "mental fight" is directed against [the] chains"...mentioned above (commerce, British imperialism and war). Neither will his sword "sleep in my hand:" he will not stop "engaging the enemy" till Jerusalem is built: the "new Jerusalem" here envisioned, and humanity's release from industry: its ugliness and its destruction of nature.
I will not cease from mental fight,
Nor shall my sword sleep in my hand
Till we have built Jerusalem
In England's green and pleasant land