Blake must have gone to the theater often because he seemed to love curtain calls. Picture 21 could be seen in that way, although there are also lots of new and original ideas in it.
Rather than reading the book Job is playing a harp, in fact he's directing a symphony while his wife plays a 'mandolin' (?).
Job now had all that he had before except that his vocation had changed to Music rather than the Law; the domestic animals gathered around.
Above the picture:
"Great and marvelous are thy works Lord God Almighty Just and True are thy Ways O Thou King of Saints" (Rev 15:3) Marvelous indeed!
Beneath the picture he inscribed verses 12, 16, and 17 of the last chapter of Job (42).
But between those verses is the same altar we found in Picture 1: he quoted Hebrew 10:6:
"In burnt offerings and sacrifices for sin thou hast had no pleasure."
Soon after he finished his "Illustrations to the Book of Job, Blake died-- with a song on his lips. Would to God that you and I might die in the same shape as the later Job and the later Blake.
We have a clearer picture in some respects at the McCormick Library at Northwestern University.
If you would like to study all these pictures at one time, here it is.