When the reasoning mind divides the contraries into categories which it labels Good and Evil it enters the state of Satan the accuser. The contraries are meant to complement and complete each other; they have no inherent moral value. They are not meant to be split asunder in opposition but to enhance one another by adding the missing piece.
The Large Color Printed Drawings of 1795
The Good and Evil Angels Struggling for Possession of a Child
 sin indeed was in the world before the law was given, but sin is not counted where there is no law.
 We know that in everything God works for good with those who love him, who are called according to his purpose.
In William Blake's Circle of Destiny Milton Percival explains the beginning of the fall thus:
"The great cosmic break in which the fine relationship of the contraries is destroyed is the work of the Spectre. Blown with pride in his emanative life, he abstracts from it a set of qualities called Good. In his arrogance he believes that these qualities which he admires are due to his own activities; he does not realize that they are but the result of the undisturbed functioning of an harmonious whole."
Jerusalem, Plate 49, (E 199) "Yet they are blameless & Iniquity must be imputed only To the State they are enterd into that they may be deliverd: Satan is the State of Death, & not a Human existence: But Luvah is named Satan, because he has enterd that State. A World where Man is by Nature the enemy of Man Because the Evil is Created into a State. that Men May be deliverd time after time evermore. Amen. Learn therefore O Sisters to distinguish the Eternal Human That walks about among the stones of fire in bliss & woe Alternate! from those States or Worlds in which the Spirit travels: This is the only means to Forgiveness of Enemies"An essential of Blake's teachings is that man can escape from the dominion of perceiving individuals as evil or good. Each has the potential of rejecting error by 'Conversing with Eternal Realities as they Exist in the Human Imagination.'
Vision of Last Judgment, (E 554)
"The Last Judgment when all those are Cast away who trouble Religion with Questions concerning Good & Evil or Eating of the Tree of those Knowledges or Reasonings which hinder the Vision of God turning all into a Consuming fire Imaginative Art & Science & all Intellectual Gifts all the Gifts of the Holy Ghost are [despisd] lookd upon as of no use & only Contention remains to Man then the Last Judgment begins & its Vision is seen by the [Imaginative Eye] of Every one according to the situation he holds The Last Judgment is not Fable or Allegory but Vision Fable or Allegory are a totally distinct & inferior kind of Poetry. Vision or Imagination is a Representation of what Eternally Exists. Really & Unchangeably. Fable or Allegory is Formd by the Daughters of Memory. Imagination is Surrounded by the daughters of Inspiration who in the aggregate are calld Jerusalem"
Vision of Last Judgment, (E 561) "A Last Judgment is not for the purpose of making Bad Men better but for the Purpose of hindering them from opressing the Good with Poverty & Pain by means of Such Vile Arguments & Insinuations"
Vision of Last Judgment, (E 562) "Here they are no longer talking of what is Good & Evil or of what is Right or Wrong & puzzling themselves in Satans Labyrinth But are Conversing with Eternal Realities as they Exist in the Human Imagination We are in a World of Generation & death & this world we must cast off if we would be Painters Such as Rafa[e]l Mich Angelo & the Ancient Sculptors. if we do not cast off this world we shall be only Venetian Painters who will be cast off & Lost from Art"
Vision of Last Judgment, (E 563) "Eternity Exists and All things in Eternity Independent of Creation which was an act of Mercy I have represented those who are in Eternity by some in a Cloud within the Rainbow that Surrounds the Throne they merely appear as in a Cloud when any thing of Creation Redemption or Judgment are the Subjects of Contemplation tho their Whole Contemplation is Concerning these things the Reason they so appear is The Humiliation of the Reasoning & Doubting Selfhood & the Giving all up to Inspiration By this it will be seen that I do not consider either the Just or the Wicked to be in a Supreme State but to be every one of them States of the Sleep which the Soul may fall into in its Deadly Dreams of Good & Evil when it leaves Paradise following the Serpent"
Vision of Last Judgment, (E 563) "The Combats of Good & Evil is Eating of the Tree of Knowledge The Combats of Truth & Error is Eating of the Tree of Life"
Vision of Last Judgment, (E 564) "Christ comes as he came at first to deliver those who were bound under the Knave not to deliver the Knave He Comes to Deliver Man the Accused & not Satan the Accuser we do not find any where that Satan is Accused of Sin he is only accused of Unbelief & thereby drawing Man into Sin that he may accuse him. Such is the Last Judgment a Deliverance from Satans Accusation Satan thinks that Sin is displeasing to God he ought to know that Nothing is displeasing to God but Unbelief & Eating of the Tree of Knowledge of Good & Evil Men are admitted into Heaven not because they have governd their Passions or have No Passions but because they have Cultivated their Understandings. The Treasures of Heaven are not Negations of Passion but Realities of Intellect from which All the Passions Emanate in their Eternal Glory The Fool shall not enter into Heaven let him be ever so Holy. Holiness is not The Price of Enterance into Heaven Those who are cast out Are All Those who having no Passions of their own because No Intellect. Have spent their lives in Curbing & Governing other Peoples by the Various arts of Poverty & Cruelty of all kinds"