The engraved copper plates for Blake's illuminated books have all been lost except for a small scrap of one plate. However the plates from which he printed the Illustrations to the Book of Job are preserved in the British Museum. John Linnell who initiated the project of having Blake engrave his illustrations to Job, was Blake's partner in printing and publishing the 22 plates of the book.
When Blake engraved Job, he was 66 years old and his health was failing, but he produced what many consider his masterpiece. The weakening of his body did not seem to affect the acuity of his eye, the steadiness of his hand or the concentration of his mind; all of which were required for such precise and sustained work.
The plates were given to the British Museum in 1919 by H. Linnell, a presumed descendant of John Linnell.
These two images from the British Museum show the engraved plate and the printed image of picture seven of the series.
The inscriptions on the plate are from this passage in Job.
 So went Satan forth from the presence of the LORD, and smote Job with sore boils from the sole of his foot unto his crown.
 And he took him a potsherd to scrape himself withal; and he sat down among the ashes.
 Then said his wife unto him, Dost thou still retain thine integrity? curse God, and die.
 But he said unto her, Thou speakest as one of the foolish women speaketh. What? shall we receive good at the hand of God, and shall we not receive evil? In all this did not Job sin with his lips.
 Now when Job's three friends heard of all this evil that was come upon him, they came every one from his own place; Eliphaz the Temanite, and Bildad the Shuhite, and Zophar the Naamathite: for they had made an appointment together to come to mourn with him and to comfort him.
 And when they lifted up their eyes afar off, and knew him not, they lifted up their voice, and wept; and they rent every one his mantle, and sprinkled dust upon their heads toward heaven.
 So they sat down with him upon the ground seven days and seven nights, and none spake a word unto him: for they saw that his grief was very great.
Edinger (Encounter with the Self, A Jungian Commentary on William Blake's Illustrations to the Book of Job) sees the three friends or comforters as repressed aspects of Job's psyche which surface with the breakdown of the ego. Blake's images in the border suggest the grief of Job at the upper corners, and the failure of the guardian shepherds to keep watch in the lower corners.
This website allows one conveniently to view all the illustrations for Job.