Plate 95, Copy A
Mercy could not be overridden by Satan's definition of holiness. Milton had an Epiphany. Satan, too, was the recipient of the Divine Mercy and would be brought into Albion, the representation of total Humanity. Satan was not to be destroyed but integrated by Los.
This appears to be Blake's recognition that the religious approaches can live side by side: that justice and mercy are both aspects of the Divine Humanity. To oppose one contrary only allows the negation to flower. If the Law prevents the Gospel from being heard, Natural Religion is allowed to flourish.
Milton, Plate 38 , (E 139)
"Satan heard! Coming in a cloud, with trumpets & flaming fire
Saying I am God the judge of all, the living & the dead Fall therefore down & worship me. submit thy supreme Dictate, to my eternal Will & to my dictate bow I hold the Balances of Right & Just & mine the Sword Seven Angels bear my Name & in those Seven I appear But I alone am God & I alone in Heavn & Earth Of all that live dare utter this, others tremble & bow Plate 39  Till All Things become One Great Satan, in Holiness Oppos'd to Mercy, and the Divine Delusion Jesus be no more Suddenly around Milton on my Path, the Starry Seven Burnd terrible! my Path became a solid fire, as bright As the clear Sun & Milton silent came down on my Path. And there went forth from the Starry limbs of the Seven: Forms Human; with Trumpets innumerable, sounding articulate As the Seven spake; and they stood in a mighty Column of Fire Surrounding Felphams Vale, reaching to the Mundane Shell, Saying Awake Albion awake! reclaim thy Reasoning Spectre. Subdue Him to the Divine Mercy, Cast him down into the Lake Of Los, that ever burneth with fire, ever & ever Amen! Let the Four Zoa's awake from Slumbers of Six Thousand Years"