If this fantastic picture comes up, you may likely find it more interesting than any words I could put here. If not here is a poor substitute (Raising the font on your display will give a larger image.)
Blake considered this painting a climax of his art. Erdman 552-66 contains what Blake had to say about it.To study A Vision of the Last Judgment is worthwhile for anyone especially interested in Blake's theology. Here is one of the passages I found most notable:
"What are all the Gifts of the Spirit but Mental Gifts whenever any Individual Rejects Error & Embraces Truth a Last Judgment passes upon that Individual" (E561).
There are many others.
The Last Judgment for Blake is the annihilating Moment when the Selfhood is no more, the Eternal Moment that overlays all that Satan can do, the Moment in each Day that Satan cannot find (Milton line 42; Erdman )136| :
"There is a Moment in each Day that Satan cannot find
Nor can his Watch Fiends find it, but the Industrious find
this Moment & it multiply and when it once is found
it renovates every Moment of the Day if rightly placed"
(Blake was industrious- imo an early riser.)
Consciousness waxes and wanes; the last judgment is the moment of maximum expansion-- a foretaste of the All that is to come. There are many such moments in our lives. Happy are we if one comes every day; in the quiet time the inconsequentials fall away to be replaced by Worship.
It's said that the old Hindu gives up everything and everyone. He retreats from life as it has been known to advance to the Eternal-- like Odysseus or Luvah or whoever he is standing on the shore of the Sea of Time and Space with the Angel beckoning him onward.
Blake "descry[ed] the immortal man who cannot die" by commiting his life to Jesus (whom he called the Forgiveness); he "closed the labors of his day" and found himself in Beulah, right on his way to Eternity. On his last day he's said to have died with a song on his lips.