Here is something I wrote 25 years ago in Chapter One of an earlier work:
"In Night vii of 4Z Urizen, the ice man, the great opposer of change, effects the metamorphosis of "fierce Orc" (Erdman page 382), personification of change, into a serpent who crawls up the Tree of Mystery. An earlier prophet had written about a serpent and a tree at the dawn of history, and since that day the two figures have served as the basic symbols of the Fall. But Moses had used the same combined image to symbolize healing, and Jesus harked back to it in predicting his own impending exit from the world and its purpose.
Knowledge of the full weight of meaning carried by serpent and tree alerts us to an impending climax in Blake's story. Back in Night i Los, the spirit of prophecy, the personification of creativity, was estranged from his emanation, Enitharmon. In Night v she gave birth to Orc, but Los chained him to earth with the Chain of Jealousy, a sort of reverse Oedipus myth. This left the creative selves a sorry shambles. But now in Night vii Enitharmon's shadow meets and unites with Los' spectre, and their issue is twofold, the Whore and the Lamb. The Whore will burn, and the Lamb will find a spotless bride."
There's no way anyone can fully appreciate the joy of this moment without having participated deeply in the agony and travail which preceded it. This is but a way of saying that there's no way anyone can appreciate the salvation of the world without having first quenched the cup of the fallenness of the world. Long ago a book appeared entitled No Cross, No Crown, suggesting that we don't appreciate what God has done simply because we refuse the cup. Jesus accepted it on our behalf, and Blake did too in his way, as does every artist or prophet or saint who follows the narrow path.