MHH has a lot of congruence with Paradise Lost:
The Marriage of Heaven and Hell came in 1790, soon after the end of the American Revolution and before the beginning of the French Revolution.
Milton lived while a British King was beheaded and replaced by the Commonwealth, an alternative form of government; he published Paradise Lost in 1667, a few years after the Restoration.
Blake and Milton were both dissenters and had republican feelings. They both lived in perilous times and might well have been branded as traitors.
Blake's overt use of Paradise Lost is in the two sets of Illustrations:
The Rev. Joseph Thomas set was dated 1807 and the larger Butts set in 1808:
Satan Arousing the Rebel Angels
Hell is a rocky place!
Standing on a 'rock in Hell' Satan streches out his arms exhorting his rebel band, who seem pretty well 'played out' after what has happened to them; four at the bottom resemble other pictures Blake did for the four zoas, but these four are in chains.
Adam lies on a couch behind Satan's knees.
From PL Book One:
The infernal Serpent; he it was whose guile,
Stirred up with envy and revenge, deceived
The mother of mankind, what time his pride
Had cast him out from Heaven, with all his host
Of rebel Angels, by whose aid, aspiring
To set himself in glory above his peers,
He trusted to have equalled the Most High,
If he opposed, and, with ambitious aim
Against the throne and monarchy of God,
Raised impious war in Heaven and battle proud,
With vain attempt. Him the Almighty Power
Hurled headlong flaming from the ethereal sky,
With hideous ruin and combustion, down
To bottomless perdition,
Whereto with speedy words the Arch-Fiend replied:—
“Fallen Cherub, to be weak is miserable,
Doing or suffering: but of this be sure—
To do aught good never will be our task,
But ever to do ill our sole delight
As being the contrary to His high will
Whom we resist. If then His providence
Out of our evil seek to bring forth good,
Our labour must be to pervert that end,
And out of good still to find means of evil;
Blake chose the cherubims of Genesis 3:24 to relate to a passage in Ezekiel 28:
"14] Thou art the anointed cherub that covereth; and I have set thee so: thou wast upon the holy mountain of God; thou hast walked up and down in the midst of the stones of fire.
 Thou wast perfect in thy ways from the day that thou wast created, till iniquity was found in thee.
 By the multitude of thy merchandise they have filled the midst of thee with violence, and thou hast sinned: therefore I will cast thee as profane out of
the mountain of God: and I will destroy thee, O covering cherub, from the midst of the stones of fire.
Blake's illustration of Satan here resembles markedly his picture of the covering cherub:
This may be the Arch-Fiend mentioned earlier; Blake called him Lucifer.
This entity has many names:
the Selfhood, and many others
Blake and Covering Cherub